question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>New user of both stackexchange and R here. My questions are about mainly about interpretation, and my dataset is quite large, so I have not included my dataframe. I have two queries (in bold). </p>
<p>Using the "metafor" package, I have a random effects model and I am trying to interpret a model with two categorica... | g64068 | [
-0.025369415059685707,
-0.030135536566376686,
-0.011346994899213314,
-0.047285400331020355,
0.044747233390808105,
-0.014101386070251465,
0.06628268212080002,
0.023964904248714447,
-0.00856513250619173,
0.005985298193991184,
-0.05075252801179886,
0.0373251810669899,
0.06446726620197296,
0.0... |
<p>I am looking to rank data that, in some cases, the larger value has the rank of 1. I am relatively new to R, but I don't see how I can adjust this setting in the rank function.</p>
<pre><code>x <- c(23,45,12,67,34,89)
rank(x)
</code></pre>
<p>generates:</p>
<pre><code>[1] 2 4 1 5 3 6
</code></pre>
<p>when I ... | g64069 | [
0.008861271664500237,
0.008634009398519993,
-0.026521872729063034,
-0.05536983907222748,
-0.00001765477645676583,
-0.0284526776522398,
0.028465131297707558,
0.013193485327064991,
-0.08188078552484512,
-0.0033297042828053236,
-0.028462223708629608,
0.018014442175626755,
0.008137615397572517,
... |
<p>I have a fairly involved homework question, I was wondering if I could get some help.</p>
<blockquote>
<p>There are two types of phone calls arriving at a switch, long-duration and short-duration. Each day the number of calls is observed up to and including the first long-duration call. This was done for 8 days a... | g64070 | [
-0.005681568756699562,
0.03762358799576759,
-0.00455821817740798,
-0.06984464079141617,
-0.007895673625171185,
-0.025040151551365852,
0.03002816252410412,
-0.028178254142403603,
-0.009956205263733864,
0.0014810649445280433,
-0.0009770692558959126,
0.02385483682155609,
0.05021089315414429,
... |
<p>I have inherited some data analysis code that, not being an econometrician, I am struggling to understand. One model runs an instrumental variables regression with the following Stata command</p>
<pre><code>ivreg my_dv var1 var2 var3 (L.my_dv = D2.my_dv D3.my_dv D4.my_dv)
</code></pre>
<p>This dataset is a panel w... | g13 | [
0.0655951201915741,
-0.07729236781597137,
-0.03653009980916977,
-0.04228559508919716,
0.05820999667048454,
-0.014954019337892532,
0.06790056824684143,
0.020759722217917442,
-0.06218299642205238,
-0.05429013445973396,
-0.02837720885872841,
0.06150782108306885,
-0.005781129933893681,
0.02817... |
<p>Background: I used a principal component analysis to re-define neighborhood boundaries. Each neighborhood is made up of at least 2 census tracts. There were 40 neighborhoods in my old model. I have 45 neighborhoods in total under my new model; 13 were altered. </p>
<p>I would like to use disease rates by gender i... | g37749 | [
0.04417542740702629,
-0.08852478861808777,
0.007593127433210611,
-0.024636713787913322,
0.0002676394651643932,
-0.0512901246547699,
0.00428226450458169,
0.004709227010607719,
-0.001553817535750568,
-0.011668472550809383,
0.0503649078309536,
0.020387619733810425,
0.04162687063217163,
0.0419... |
<p>I have 20 time series that span the same period (100 days each), from 4 species sampled at 5 different location. I made a loop to perform a breakpoint analysis on all of them, resulting in 0 to 3 breakpoints per series (with confidence intervals). </p>
<p>How can I check whether some points are common between some ... | g64071 | [
0.028737181797623634,
-0.020345719531178474,
-0.02713623456656933,
-0.07924611121416092,
-0.006711014546453953,
-0.04595495015382767,
0.053986433893442154,
-0.015909764915704727,
-0.044685427099466324,
0.0021265901159495115,
-0.023158080875873566,
0.03524785116314888,
0.059271588921546936,
... |
<p>I have been busy building an explainatory regression model for a companies' social behavior. In the table below you find the variables, ordered by theme. The <code>English</code> to <code>French</code> variables are dummies, indicating the legal system a company has to comply with.</p>
<p><img src="http://i.stack.i... | g64072 | [
0.013547019101679325,
0.020253721624612808,
-0.023783933371305466,
-0.0059722475707530975,
0.09499640762805939,
-0.040984343737363815,
0.042370907962322235,
-0.0095127634704113,
-0.02001936547458172,
-0.01938539743423462,
-0.039186760783195496,
-0.0100407088175416,
0.04872724041342735,
0.0... |
<p><strong>Question:</strong> With a 10 dimensional MCMC chain, let's say I'm prepared to hand you a matrix of the draws: 100,000 iterations (rows) by 10 parameters (columns), how best can I identify the posterior modes? I'm especially concerned with multiple modes.</p>
<p><strong>Background:</strong> I consider mys... | g64073 | [
-0.010513371787965298,
0.0185833889991045,
0.0029429560527205467,
-0.09587213397026062,
-0.014825149439275265,
-0.08074499666690826,
-0.016471730545163155,
-0.015498785302042961,
-0.027871958911418915,
0.01343862246721983,
-0.016654588282108307,
-0.0420403927564621,
0.0540551096200943,
0.0... |
<p>I'm trying to understand why there tends to be correlation (as measured by the standard Pearson correlation coefficient) between $x$ and $x^2$ (for instance if $x$ is uniformly distributed). </p>
<p>It's my understanding that the Pearson correlation coefficient only measures <em>linear</em> relationships. $x$ and $... | g41530 | [
0.059743497520685196,
-0.04837515577673912,
-0.02231498807668686,
-0.050390683114528656,
0.025835230946540833,
0.012105083093047142,
-0.015020889230072498,
-0.0038307274226099253,
-0.02074696123600006,
-0.062079790979623795,
0.0062236781232059,
0.011256080120801926,
-0.02017146721482277,
0... |
<p>So, I was standing in line for a Paramore concert for a very long time this past weekend because the boyfriend wanted to be up front during the show. I got to thinking, what would be the optimal time to show up for a concert to minimize both the time waiting and the number of people in front of you? I immediately th... | g41531 | [
-0.030222272500395775,
0.025785543024539948,
-0.011063979007303715,
-0.02309298701584339,
-0.01780211739242077,
-0.013241764158010483,
0.04323204234242439,
0.025593683123588562,
-0.031387969851493835,
0.04932781308889389,
-0.04096975550055504,
-0.012391875497996807,
-0.036940377205610275,
... |
<p>I have a logistic model fitted with the following R function:</p>
<pre><code>glmfit<-glm(formula, data, family=binomial)
</code></pre>
<p>A reasonable cutoff value in order to get a good data classification (or confusion matrix) with the fitted model is 0.2 instead of the mostly used 0.5.</p>
<p>And I want to... | g64074 | [
0.03138232231140137,
-0.04149983078241348,
0.005882227793335915,
-0.024949651211500168,
0.02019384130835533,
-0.028377598151564598,
0.009302248246967793,
-0.006857198663055897,
-0.07570964843034744,
-0.01584678888320923,
-0.009907416068017483,
0.06179326772689819,
0.04668082669377327,
-0.0... |
<p>Im not sure what test to conduct when I have 3x3 matrix of data and still account for availability.</p>
<p>So, in a simple chi square you have an observed observation and then you are often able to calculate the expected based on some proportion. Without talking in total abstract, Ive got moose counts of foraging ... | g117 | [
-0.013187008909881115,
-0.04089246317744255,
-0.016701331362128258,
-0.04339410364627838,
-0.000634740456007421,
-0.026244504377245903,
0.05086054652929306,
0.03299884870648384,
-0.004890087526291609,
-0.010178375989198685,
0.016158446669578552,
0.019035687670111656,
0.030051331967115402,
... |
<h2>I got this interview question. Would like to know the correct answer:</h2>
<p>In our population, there are 10,000 customers. We sample 1,000 of these people to offer a product. We know </p>
<pre><code> 1. Some don’t accept offer anymore.
2. Some accept if we call them
3. Some accept anyway.
</code></pre>
<p>... | g64075 | [
0.03050648793578148,
0.015080980956554413,
0.006942644715309143,
0.01085459254682064,
0.01180756650865078,
0.005716403946280479,
0.012732340954244137,
0.06333182752132416,
-0.04810822382569313,
-0.009061641991138458,
-0.00849396176636219,
0.0786840170621872,
-0.03542407229542732,
0.0217471... |
<p>I have a question. I have several (e.g. VAR01, VAR02, VAR03 ) variables. They are measured twice, one with an intervention and one without intervention. </p>
<p>I want to test the hypothesis that the greater change in VAR01 (before and after the intervention) will also result in greater changer in VAR03.</p>
<p>W... | g22795 | [
0.027266422286629677,
-0.056784000247716904,
0.0084204887971282,
-0.02766181342303753,
0.020741745829582214,
-0.013807850889861584,
0.015112160705029964,
0.05347402021288872,
-0.027888521552085876,
0.010799719952046871,
-0.013550762087106705,
0.03719528391957283,
0.03291789069771767,
0.052... |
<p>I have a dependent variable <strong>w</strong> with independent variable <strong>x</strong> representing time, which is clustered by variable <strong>site</strong>. In addition, I have indicator variables for 3 time period: <strong>i1, i2, i3</strong>, which correspond to three distinct time periods along the timel... | g22044 | [
-0.006121430080384016,
-0.08075796067714691,
0.0008418220677413046,
-0.030710777267813683,
-0.03839648514986038,
0.013300932943820953,
0.007450740318745375,
0.04185838624835014,
-0.04334982857108116,
-0.020330701023340225,
-0.026256008073687553,
0.0197964645922184,
0.027238810434937477,
0.... |
<p>I was wondering if you could provide some advice/feedback on a problem I have been having with detecting multi-colinearity.</p>
<p>First, the variables which I am using are not normally distributed, hence I am using a non - parametric measure (Spearman's rank).
There are several variables with a high coefficient (... | g64076 | [
0.014894130639731884,
-0.040503837168216705,
-0.03540010750293732,
-0.05573349446058273,
0.06905726343393326,
-0.02398846112191677,
0.03793852776288986,
0.0007070119027048349,
0.0038837105967104435,
-0.003468296956270933,
-0.08859208226203918,
-0.00031731437775306404,
-0.02562311664223671,
... |
<p>I am following up the question I asked <a href="http://stats.stackexchange.com/questions/78623/ordinal-model-comparison-lower-deviance-but-lower-accuracy-is-this-possible">here</a> with a more general one, as the reason why I am seeking to calculate the accuracy of my ordinal regression models is to use it as a meas... | g24180 | [
-0.0019606524147093296,
-0.052814334630966187,
0.007412179838865995,
-0.03008028119802475,
0.03780869394540787,
-0.005620033945888281,
0.007351265288889408,
0.030262229964137077,
-0.01651988923549652,
0.010903775691986084,
0.032767653465270996,
0.03098687157034874,
0.05170753598213196,
-0.... |
<p>I'm trying to find a correlation or repeated patterns between several sets of data, at this stage 15, but I plan to expand this to several hundred data sets.</p>
<p>At the moment I am plotting the data in sets of 3s on a line chart similar to the image below and trying to see if there are any patterns or correlatio... | g64077 | [
0.024590834975242615,
0.04552948847413063,
-0.017166104167699814,
-0.0699283629655838,
-0.02469080127775669,
-0.031307436525821686,
0.05379686504602432,
-0.04576670750975609,
-0.025173218920826912,
-0.04940400272607803,
-0.004176512826234102,
-0.0334886759519577,
0.07597881555557251,
0.014... |
<p>I wish to compare the success ratio of offers according to the day of the week.
Here is a table with the last column giving the average success ratio across all offers for that weekday. It <em>seems</em> that Mondays are performing the best (0.33 success ratio)</p>
<pre><code>tab = table(t$weekday,t$repeater)
cbind... | g64078 | [
-0.058093588799238205,
0.0011363880475983024,
-0.023562243208289146,
-0.05488171428442001,
0.007638502866029739,
-0.027550680562853813,
0.030376482754945755,
-0.05238986015319824,
-0.03524341806769371,
-0.009205942042171955,
0.05209536477923393,
-0.010285919532179832,
0.0601547509431839,
0... |
<p>From Bishop's book I know an observed variable in a Markov Chain does work as d-separation element. What I am more uncertain about is what happens to the message itself.</p>
<p>In the sum-product algorithm, instead of summing over that specific variable, I just use the observed value for the potential function mult... | g22051 | [
-0.00804903358221054,
-0.02589961513876915,
0.00376530853100121,
-0.05073653906583786,
0.009464499540627003,
-0.011497006751596928,
0.0673927292227745,
0.02503897435963154,
0.002511939499527216,
-0.02014784887433052,
-0.08263688534498215,
0.05282047763466835,
0.00909459963440895,
0.0005237... |
<p>I have a binary response variable (it is a presence/absence variable) and a ordinal discrete predictor:</p>
<pre><code>response : [1 0 1 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 ... ]
predictor : [1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 ... ]
</code></pre>
<p>I'd like to know whether there is a higher probability to encoun... | g64079 | [
0.007965012453496456,
-0.020224347710609436,
0.007244388107210398,
-0.024075118824839592,
0.03764397278428078,
-0.022191515192389488,
0.027543405070900917,
0.021831562742590904,
-0.041825439780950546,
-0.054068755358457565,
0.021107779815793037,
0.033403053879737854,
0.016117073595523834,
... |
<p>Let us assume we have two classifiers <code>C1</code> and <code>C2</code> which are based on different feature vectors, <code>V(C1)=[A,B,C]</code> and <code>V(C2)=[A,B,C,D,E,F]</code>. Both vectors share the same features <code>A,B,C</code> but <code>V(C2)</code> has three additional features (<code>D,E,F</code>) an... | g64080 | [
0.022209608927369118,
-0.05808611586689949,
0.016503682360053062,
-0.022433210164308548,
0.007682035677134991,
-0.046553608030080795,
0.05143817886710167,
0.010662303306162357,
-0.05835528299212456,
-0.02157379873096943,
0.020160432904958725,
0.04996455833315849,
0.03880229592323303,
0.037... |
<p>I have count data passenger as Y. The data look like this<img src="http://i.stack.imgur.com/zRmgy.png" alt="enter image description here">, as many of the values are 1 (about 18%.) </p>
<p>Does it make sense that I take a log of it, and take it as a dependent variable in a generalized linear model with Poisson dis... | g22056 | [
-0.012028674595057964,
0.0076536862179636955,
-0.020525570958852768,
-0.03239641338586807,
-0.03422227501869202,
0.013588224537670612,
-0.012201119214296341,
-0.012243405915796757,
-0.05339062213897705,
-0.02239318937063217,
-0.021465813741087914,
-0.030476374551653862,
0.02356719970703125,
... |
<p>I have a dataset where the samples are dependent, belong to different groups, and measurements were taken over time. It looks like this:</p>
<pre>
Subject Group Time Value
S1 G1 12h 5.55
S1 G1 24h 7.63
S1 G1 36h 9.88
S2 G2 12h 3.26
S2 G2 24h 4.57
S2 G2 36h 6.44
S3 G3 12h 3.23
S3 G3 24h 4.10
S3 ... | g64081 | [
-0.026379557326436043,
-0.04009539633989334,
-0.01619131863117218,
-0.056908540427684784,
-0.057448163628578186,
-0.02325529232621193,
0.015047968365252018,
-0.02683890424668789,
-0.08789245784282684,
0.02455507032573223,
-0.016369562596082687,
0.04102557152509689,
-0.039213426411151886,
0... |
<p>EDIT: I have solved this problem myself. The problem with the simulation below is that the omitted variable should not be included in the 'true model'. I have written a blog post with a more detailed analysis <a href="http://diffuseprior.wordpress.com/2012/08/15/probit-models-with-endogeneity/" rel="nofollow">here</... | g64082 | [
0.0033308255951851606,
-0.06183963641524315,
-0.0012378448154777288,
-0.038540907204151154,
0.05378510802984238,
0.009423775598406792,
0.012011541984975338,
-0.018544461578130722,
-0.04843047633767128,
-0.012161931954324245,
0.0017338203033432364,
-0.0010708329500630498,
-0.00587312737479805... |
<p>I am looking at a situation where I have a population of about 150-170. I am testing for the absence or presence of a particular property. Given the population, I can easily figure out the sample size needed for various confidence levels. </p>
<p>However, I have read in a number of places (e.g., <a href="http://en.... | g64083 | [
0.016953857615590096,
0.03550773859024048,
-0.01762964576482773,
-0.04949767887592316,
0.025867708027362823,
-0.024297136813402176,
0.038590531796216965,
0.07447852939367294,
-0.03270091488957405,
-0.04262329638004303,
-0.00612818356603384,
-0.011594990268349648,
0.0460331104695797,
0.0373... |
<p>Can the concept of odds ratio be applied in the confusion matrix to measure the degree of association between responsive and non responsive documents labelled by the system and user? Should the terms of the confusion matrix be rearranged while computing odds ratio?
The confusion matrix generated after my classificat... | g64084 | [
-0.020144494250416756,
-0.018264664337038994,
-0.004897700622677803,
-0.028606891632080078,
-0.003490723203867674,
-0.034134820103645325,
0.0856001153588295,
0.035182785242795944,
0.024777380749583244,
-0.004319647327065468,
0.0338824987411499,
-0.006241766270250082,
0.04216807708144188,
-... |
<p>I understand that PCA and SVD are similar - PCA removes the mean and SVD doesn't? I think I have an understanding of PCA - you would use it to reduce dimensions of data and separate it out into linear combinations of variables that explain the largest variance of the SS.</p>
<p>But I can't grasp that same concept ... | g49691 | [
0.09258834272623062,
-0.029428796842694283,
0.020621007308363914,
0.048737604171037674,
-0.06675974279642105,
-0.0178657379001379,
0.057735174894332886,
0.04639020189642906,
-0.02510291524231434,
-0.0476437546312809,
0.03037356026470661,
0.002685501240193844,
0.06616910547018051,
0.0189491... |
<p>Let $X$ and $Y$ be independent, continuous random variables.</p>
<p>The PDF of a sum $W=X+Y$ is given by the convolution formula $$ f_{X+Y} (w) = \int_{-\infty}^{\infty} f_X(x) f_Y(w-x)\,\,dx$$</p>
<p><br>
In <a href="https://courses.edx.org/courses/MITx/6.041x/1T2014/courseware/Unit_6_Further_topics_on_random_var... | g22062 | [
-0.001935079344548285,
-0.045781396329402924,
-0.0064141894690692425,
-0.04638567194342613,
-0.01758660189807415,
-0.030966049060225487,
0.005767651833593845,
0.003215201897546649,
-0.045601457357406616,
0.011543570086359978,
0.003888813080266118,
0.03471410647034645,
-0.005219004116952419,
... |
<p>I've come across some past questions asking about using a linear probability model in place of a probit model when the data generating function has uniformly distributed errors. However, I am uncertain about deriving the variance of the linear probability model. The problem is as follows:</p>
<p><img src="http://i.... | g64085 | [
0.04460715875029564,
-0.04003763198852539,
-0.002415454015135765,
-0.02890252321958542,
0.03663536533713341,
0.053527187556028366,
-0.007658845745027065,
0.030447157099843025,
-0.07019302248954773,
0.012705469503998756,
-0.01721031963825226,
-0.04688456654548645,
0.0329919271171093,
-0.000... |
<p>Could you recommend an R package for estimating a (frequentist) multilevel Weibull regression model? </p>
<p>I need to model random intercepts, random slopes, as well as a cross-classified structure. </p>
<p><strong>UPDATE:</strong>
It seems like there is currently no "easy" solution for that. I decided to leave i... | g64086 | [
0.009727271273732185,
-0.039203815162181854,
-0.014004507102072239,
0.037028200924396515,
-0.04086862504482269,
-0.06128816679120064,
0.027255943045020103,
0.01597040891647339,
0.00819240603595972,
0.01075668353587389,
-0.00020812125876545906,
-0.00928743090480566,
0.024987144395709038,
0.... |
<p>I am trying to calculate sensitivity, specificity, and odds ratio of a data set, they are numerical values of percentages from 0% to 100%. How should I do the calculation?</p>
<p><a href="http://en.wikipedia.org/wiki/Sensitivity_and_specificity" rel="nofollow">Wikipedia</a> has the formula:
$$sensitivity = \frac{t... | g64087 | [
0.026557382196187973,
-0.020128030329942703,
-0.027363771572709084,
-0.015155836008489132,
-0.01033348124474287,
-0.026607509702444077,
0.019004467874765396,
0.06425951421260834,
-0.04703867435455322,
-0.003314387518912554,
0.007256416603922844,
0.061059754341840744,
0.07677722722291946,
0... |
<p><strong>Step 1. To answer "Final Question"</strong> </p>
<p>( linked: "<a href="http://stats.stackexchange.com/questions/79246/the-final-question-order-of-differencing-to-achieve-stationary-and-interpreta">THE FINAL QUESTION : Order of differencing, to achieve stationary and interpretation of arima() , acf, pacf?<... | g64088 | [
0.003662334755063057,
-0.1030322015285492,
-0.0034748504403978586,
-0.032047614455223083,
0.04419375956058502,
-0.029247546568512917,
0.09192976355552673,
0.010676734149456024,
-0.05419670790433884,
0.003339966991916299,
0.047109924256801605,
0.04739781841635704,
0.01795361004769802,
-0.05... |
<p>As a neophyte in statistics, I've got a question and a very long plane ride to try to work on the problem / read.</p>
<p>I've got n~100000 customers who make phone calls through my service. They all have different rate plans and start dates. I'd like to estimate their usage in the future month based upon their past... | g64089 | [
-0.0385090634226799,
0.010904940776526928,
-0.009283199906349182,
-0.004913870245218277,
-0.061433665454387665,
-0.04082082584500313,
0.0028696805238723755,
-0.005068998318165541,
-0.015425845980644226,
-0.012988245114684105,
0.0044730608351528645,
-0.0029531207401305437,
0.07418964058160782... |
<p>I refer to the text provided from <a href="http://www.healthknowledge.org.uk/public-health-textbook/research-methods/1a-epidemiology/numerators-denominators-populations" rel="nofollow">http://www.healthknowledge.org.uk/public-health-textbook/research-methods/1a-epidemiology/numerators-denominators-populations</a> be... | g64090 | [
0.057036638259887695,
-0.01651800610125065,
0.0007062720833346248,
-0.034538090229034424,
-0.005809898488223553,
0.010010247118771076,
0.015144852921366692,
0.04133274406194687,
-0.011860068887472153,
-0.004199966322630644,
0.010624171234667301,
0.04912658408284187,
0.03682052716612816,
0.... |
<p>I saw from their Wikipedia page, and my impression is that both are developed when the data is nested. Are multilevel model and random effect model the same concept? If they are not, what are their differences and relations? Thanks!</p> | g22068 | [
0.03621301427483559,
-0.015206980518996716,
-0.00211435928940773,
0.03744533285498619,
0.00599280558526516,
0.0116350082680583,
0.004830206278711557,
0.007916783913969994,
0.031054284423589706,
-0.05749860778450966,
-0.056379880756139755,
0.005831264890730381,
0.08366774022579193,
-0.00497... |
<p>i've been trying to find an answer to this but I haven't been successful. I encounter a problem when adding supplementary individuals to PCA. The variance of the factor scores decreases dramatically when adding supplementary observations. </p>
<p>I am doing a PCA in R on genom data. The datatable has 1645 rows (ind... | g64091 | [
0.02723485417664051,
-0.00560294184833765,
0.0072757587768137455,
-0.08611082285642624,
0.025084951892495155,
-0.013637939468026161,
0.07426625490188599,
0.04653879255056381,
-0.0007391889812424779,
-0.005532766226679087,
-0.018193233758211136,
-0.003187601687386632,
-0.007191401906311512,
... |
<p>I am doing a Monte Carlo sampling from the null hypothesis in order to estimate a p-value of my data. Normally I would do, say, 1000 Monte Carlo runs, count the number of runs where I get values of my statistic at least as extreme (let's say 3), and report a p-value of p=0.003. However, in this particular case all M... | g64092 | [
0.034436192363500595,
0.017342079430818558,
-0.0049934000708162785,
-0.04346185922622681,
-0.04707005247473717,
-0.001433372963219881,
-0.017192751169204712,
0.06298942118883133,
-0.014466219581663609,
-0.04463497921824455,
-0.014646358788013458,
0.03715350478887558,
0.04791860654950142,
0... |
<p>I am fitting a regression with ARMA errors using the base R function <code>arima()</code> and the <code>Arima()</code> function from the <code>forecast</code> package. </p>
<p>The estimated coefficients from both are identical. My problem comes from using <code>arima.errors()</code> on these two models, and using ... | g22803 | [
0.060413528233766556,
-0.09171005338430405,
0.003851400688290596,
-0.0056292349472641945,
0.0035560489632189274,
-0.002249866258352995,
0.04104165732860565,
-0.014445362612605095,
-0.03671034052968025,
-0.009465781971812248,
0.029074599966406822,
0.024738557636737823,
0.04230445995926857,
... |
<p>How does one calculate the distribution of a random variable $Z = X + Y$, where $X$ is Poisson distributed and $Y$ is normally distributed and independent of $X$? How to do that in general case? Do you know any textbook about this topic? It's really hard for me to seach on this topic, because I don't know what to ca... | g64093 | [
0.033673450350761414,
0.02066907100379467,
-0.00898952130228281,
-0.017598431557416916,
-0.04758697375655174,
-0.037979792803525925,
-0.005425626877695322,
0.02413366176187992,
0.026983601972460747,
0.012485213577747345,
-0.02295033447444439,
0.01192497182637453,
-0.01980477198958397,
0.01... |
<p>Let $X=\min(U,V)$ and $Y=\max(U,V)$ for independent uniform(0,1) variables $U$ and $V$.
What's the covariance of $X$ and $Y$? Could you develop some calculations, especially regarding the computation of $\mathbb{E}XY$?</p> | g64094 | [
-0.03259333595633507,
-0.05690356343984604,
-0.01786855235695839,
0.017426248639822006,
0.01295007485896349,
-0.004864269867539406,
-0.00046260570525191724,
0.04743243753910065,
-0.021584177389740944,
0.04200953617691994,
-0.034107405692338943,
0.05131551995873451,
0.00040804973104968667,
... |
<p>I have a very small data sets of web traffic to compare the effect of performing advertising over five days or seven days. Yes, running a test over 7 days would definitely give me more traffic but I would like to know if the traffic is significantly higher and worth my consideration.</p>
<p>I run each test for 2 we... | g32277 | [
-0.014680959284305573,
0.011776335537433624,
-0.030011042952537537,
-0.04274044185876846,
0.012471352703869343,
-0.015273976139724255,
0.09093726426362991,
-0.011777343228459358,
-0.004369492642581463,
-0.037544552236795425,
-0.020100299268960953,
0.03369029611349106,
-0.010533246211707592,
... |
<p>A campus population of size N=9000 is to be surveyed by a stratified sample for the prevalence of a certain disease based upon three strata of respective sizes $N_h$ = 1000, 3000, and 5000 for h = 1, 2, 3. The costs of sampling individuals from theses strata are estimated to be respectively 40, 20, and 10 dollars p... | g28826 | [
0.0355120413005352,
-0.025256309658288956,
0.01873842068016529,
-0.024763936176896095,
-0.02217770367860794,
0.006711664609611034,
0.010968881659209728,
-0.011750789359211922,
0.006922928150743246,
0.022803789004683495,
0.03844910487532616,
0.03873317688703537,
-0.007377400994300842,
0.005... |
<p>I'have fitted a mixed model in SPSS with fixed and random effects, and I would like to know what do the Fixed effects contrasts (type III) mean... In my model they are significant (e.g F=23.9; p=.012), but in the parameters estimates table the fixed variables are not significant... How should I interpret it? Thank y... | g64095 | [
0.006964104250073433,
-0.043605245649814606,
-0.020559212192893028,
-0.0348639078438282,
0.05356506258249283,
0.03761571645736694,
-0.012370118871331215,
0.05618807300925255,
0.011438162066042423,
-0.043806783854961395,
-0.057863060384988785,
0.015714621171355247,
0.008474337868392467,
0.0... |
<p>This <a href="http://stats.stackexchange.com/questions/29563/why-are-rlm-regression-coefficient-estimates-different-from-lm-in-r">thread</a> discusses an issue found in robust regression estimation: when the model fit is particularly low, although significant, the Huber estimator with a standard $k$ value of, say, 2... | g47161 | [
0.05545699596405029,
-0.10043690353631973,
-0.024977579712867737,
0.03903831169009209,
-0.01655876822769642,
-0.001326491474173963,
0.04906206205487251,
-0.004377047065645456,
-0.0672401487827301,
-0.05159482732415199,
0.003623394062742591,
-0.024897702038288116,
0.044314686208963394,
0.00... |
<p>My question is straightforward: I want to do statistical classification in a database, mostly of floats, but one of the fields of the data is a big text. By <em>big</em> I mean up to 1000 words. </p>
<p>What is the best way to deal with that?</p>
<p><strong>UPDATED</strong>: It's supposed to be <em>supervised lear... | g64096 | [
0.050184279680252075,
-0.0034543462097644806,
-0.009105813689529896,
-0.06652966141700745,
-0.007385186851024628,
-0.028407853096723557,
0.02269621379673481,
0.06581763178110123,
-0.03273088112473488,
-0.029832040891051292,
-0.0036638262681663036,
0.010010513477027416,
0.08195372670888901,
... |
<p>I have $2$ $n\times p$ matrices, where $n$ are the rows (samples), and $p$ the columns (measurements). Each matrix has samples and measurements from different groups. I call these the "raw" data. I've conducted a principal components analyses of the complete raw data, and computed the mean of each PC score by group... | g22079 | [
-0.006288010627031326,
-0.053553320467472076,
0.021877121180295944,
-0.038068078458309174,
-0.004747951403260231,
-0.048997052013874054,
0.07168342173099518,
-0.020216792821884155,
-0.06965193152427673,
-0.014080013148486614,
0.025318685919046402,
0.046861421316862106,
-0.040698081254959106,... |
<p>I was recently looking at the National Survey of Family Growth (US Census Bureau) and noticed that the numbers on the median column were not whole numbers, but rather numbers like 5.1 and 4.6. (Not 5.1 thousand or 5.1 million, just 5.1.)</p>
<p>This seemed unusual to me, so I looked to see if there was a note. Ther... | g64097 | [
-0.006572335492819548,
0.014106505550444126,
-0.00727992644533515,
-0.000581166532356292,
-0.006614601239562035,
-0.027583304792642593,
0.00974682904779911,
-0.009357794187963009,
-0.029607020318508148,
-0.06378091126680374,
0.024561304599046707,
0.0034778746776282787,
0.005282093770802021,
... |
<pre><code>lm(y~x1 + x2 -1)
</code></pre>
<p>where <code>x1</code> is a continuous numerical variable and <code>x2</code> is a categorical factor variable with 4 levels.</p>
<p>Is there a way to measure the "correlation" between the <code>x1</code> variable and each level of the factor variable <code>x2</code>? By pu... | g41579 | [
0.011851383373141289,
-0.08190534263849258,
-0.01867326907813549,
-0.07911708205938339,
0.03735341876745224,
-0.036305662244558334,
0.028590308502316475,
0.018425852060317993,
-0.06068020686507225,
0.005859193857759237,
-0.05061974376440048,
0.05475929006934166,
0.01629902608692646,
0.0700... |
<p>There is some process running (for example, network traffic generation). It has two different input conditions which when applied create 2 process cases (#1 and #2). There is a need to compare these cases' results by finding some sort of ratio that will show how much they differ. <br/>
There are few criteria that we... | g64098 | [
0.04868818074464798,
-0.037168800830841064,
-0.024786466732621193,
-0.05029992386698723,
0.022981734946370125,
-0.045205775648355484,
0.07126741856336594,
0.003247712505981326,
-0.05432771518826485,
-0.016367340460419655,
-0.0017536059021949768,
0.011555103585124016,
0.02777859941124916,
0... |
<p>I need to find the pdf of a random variable which is a mixture of discrete and continuous random variables. I have seen on this website but it does not exist in the general case, but maybe in this one it does.</p>
<p>In any case, I have $X \sim Bern(p)$ where $p$ is known, and I have $Y = XW+(1-X)Z$ where $W,Z$ are... | g64099 | [
0.01393077615648508,
-0.08529659360647202,
-0.010993275791406631,
-0.05721892789006233,
-0.03484096750617027,
-0.04526127129793167,
0.020808717235922813,
-0.006078637670725584,
-0.016543658450245857,
-0.025640500709414482,
0.018344992771744728,
0.015431937761604786,
-0.024239443242549896,
... |
<p>In particular, I am looking for a textbook which will go over the details of derivations (including all calculus and linear algebra) for learning models and concepts such as logistic regression, Gaussian Discriminant Analysis, with full proofs for variants like Gaussian Naive Bayes.</p>
<p>Books such as "Elements o... | g64100 | [
0.06106605380773544,
-0.03135068342089653,
0.01096469908952713,
-0.02046736143529415,
-0.012040216475725174,
-0.00795360654592514,
0.007231660652905703,
0.006353818811476231,
0.018753569573163986,
-0.008390149101614952,
0.01873277872800827,
0.022755160927772522,
0.07540878653526306,
-0.000... |
<p>I have data from a survey comprised of several measures that used different Likert-type scaling (4-, 5-, and 6-point scales). I would like to run a principal components analysis using the data from these measures. It seems to me that I need to transform this data in some way so that the power of all items is equiv... | g22080 | [
0.01648486778140068,
0.0016273771179839969,
-0.01932714320719242,
-0.06759784370660782,
-0.024165213108062744,
-0.02700221724808216,
-0.0256924107670784,
0.013586936518549919,
-0.026818402111530304,
0.027724051848053932,
0.010311526246368885,
0.02253842167556286,
0.013558978214859962,
-0.0... |
<p>I recently asked a question regarding general principles around <a href="http://stats.stackexchange.com/questions/3460/reviewing-statistics-in-papers">reviewing statistics in papers</a>. What I would now like to ask, is what particularly irritates you when reviewing a paper, i.e. what's the best way to really annoy ... | g64101 | [
0.034996770322322845,
0.027388781309127808,
0.007300833240151405,
-0.08903945982456207,
-0.01970689743757248,
-0.019670667126774788,
-0.02348470315337181,
0.021429704502224922,
-0.0301401074975729,
0.06516429036855698,
0.07798056304454803,
-0.023485464975237846,
-0.00040565815288573503,
-0... |
<p>I have three variables,<br>
1. Irrational Beliefs (Categorical)<br>
2. Anxiety State/ Trait (Categorical)<br>
3. Personality Traits (Categorical)<br>
Which statistical analyses can be used?</p> | g22085 | [
0.010148436762392521,
-0.0012107820948585868,
0.013735955581068993,
0.0044794874265789986,
0.007204149384051561,
0.005187356378883123,
-0.02661558799445629,
0.026497600600123405,
0.0012693032622337341,
-0.019004100933670998,
0.018708301708102226,
0.00039620851748622954,
-0.021192189306020737... |
<p>I was told that cross-validation and the Bayesian method can overcome the overfitting problem. I was told that comparison of models in a Bayesian way is actually doing cross-validation... What is the explanation? </p> | g28830 | [
0.03919576108455658,
0.02135256677865982,
0.017101993784308434,
-0.022763177752494812,
0.01588364690542221,
0.04141123592853546,
0.012176492251455784,
-0.014436802826821804,
-0.05020652711391449,
0.03375859558582306,
-0.015180958434939384,
-0.02671876549720764,
0.015496091917157173,
0.0298... |
<p>Naive Bayes classifiers are a popular choice for classification problems. There are many reasons for this, including:</p>
<ul>
<li>"Zeitgeist" - widespread awareness after the success of spam filters about ten years ago</li>
<li>Easy to write</li>
<li>The classifier model is fast to build</li>
<li>The model can be ... | g22087 | [
0.011719432659447193,
-0.032026827335357666,
0.02722654677927494,
0.00927125383168459,
-0.0010836997535079718,
-0.04147186130285263,
0.01867932826280594,
0.048022154718637466,
-0.031322866678237915,
-0.03282158821821213,
0.00508206756785512,
0.029586197808384895,
0.055281247943639755,
0.05... |
<p>Excuse me I'm not an English speaker and I have no idea whatsoever whether there is any standard naming scheme. And since I don't want to use names I have read in some books I will be overly descriptive. </p>
<p>Let's suppose I want to describe a dataset containing data for prediction of weather pollutants. Each ro... | g41586 | [
-0.018698612228035927,
-0.053995199501514435,
-0.006721125449985266,
-0.07164143770933151,
0.004488777834922075,
-0.030241619795560837,
0.01673777773976326,
0.011556200683116913,
-0.07039062678813934,
-0.028718790039420128,
0.02877524122595787,
-0.007983353920280933,
0.09250522404909134,
-... |
<p>I have <a href="http://en.wikipedia.org/wiki/Gamma_distribution#Summation">read</a> that the sum of gamma distributions with the same scale parameter is another gamma distribution. I've also seen the paper by <a href="http://www.ism.ac.jp/editsec/aism/pdf/037_3_0541.pdf">Moschopoulos</a> describing a method for the ... | g64102 | [
-0.02137286402285099,
0.014569021761417389,
-0.019462082535028458,
-0.08926118165254593,
0.010559994727373123,
-0.03585819527506828,
-0.004499730654060841,
-0.0040089827962219715,
-0.04699452966451645,
0.04582235962152481,
0.03763820603489876,
-0.015360764227807522,
0.06779161095619202,
0.... |
<p>I am new to WinBUGS and OpenBUGS.
I just fit a model to try an example. I was wondering whether I can get predictions generated by WinBUGS/OpenBUGS. If not, are there any convenient ways available (with the help of other applications, R, for example) to do this?</p>
<p>Thanks a lot.</p> | g41587 | [
0.0005588883650489151,
-0.05316786840558052,
0.022194840013980865,
-0.006551648490130901,
-0.038666948676109314,
-0.026544256135821342,
0.004638088867068291,
0.04925112426280975,
-0.06199021264910698,
-0.061962585896253586,
-0.03090955875813961,
-0.013586146757006645,
0.045777127146720886,
... |
<p>I am currently using Matlab to generate random forests. I am using the <code>TreeBagger</code> class with the function <code>oobError</code>. I can plot a 2D figure which puts my tree count on the X-axis (IKA weak learners count) and classification error is on the Y-axis.</p>
<p>My question is: How can I interpret ... | g47218 | [
-0.020547764375805855,
-0.029235512018203735,
0.016663240268826485,
-0.0225968137383461,
0.03998741880059242,
-0.0015304193366318941,
0.01856786385178566,
0.022369444370269775,
-0.053747281432151794,
0.032835159450769424,
-0.01443013921380043,
0.021444594487547874,
0.0687979906797409,
0.03... |
<p>I want to design a study that will eventually allow me to estimate centile curves for a given longitudinal outcome measured in a sample. I want to simulate data that I can then use to evaluate likely sample sizes needed to estimate the <a href="http://www.gamlss.org/?page_id=1302" rel="nofollow">LMS centile curves</... | g64103 | [
-0.0029328230302780867,
-0.008183550089597702,
0.0010467005195096135,
-0.03515606373548508,
-0.05775509029626846,
-0.017997363582253456,
-0.028992604464292526,
0.017695218324661255,
-0.04835684224963188,
0.009110769256949425,
0.03640381991863251,
-0.02224963717162609,
0.03509999439120293,
... |
<p>Does anyone know how the eigenvalues are adjusted to make a non-positive definite matrix into a positive definite matrix in Matrix package? I mean in nearPD function.</p> | g64104 | [
-0.023539524525403976,
-0.07134974747896194,
-0.0017120501725003123,
-0.038262560963630676,
0.016486756503582,
0.015300109051167965,
0.03193993866443634,
0.06338917464017868,
-0.05528024211525917,
0.011941210366785526,
0.012952088378369808,
-0.00890521053224802,
0.03905798867344856,
0.0516... |
<p>What is the apropriate statistic to measure the goodness-of-fit in Boosted Regression Tree (or Gradient Boosting Regression) with continuous response?
How can I calculate the coefficient of determination (R²) in the train and test data?
If I calculate the R² as bellow, How can I calculate the intercept-only model?<... | g22090 | [
-0.007455446291714907,
-0.06884738057851791,
-0.024413153529167175,
-0.022531412541866302,
-0.007741513662040234,
-0.0093586640432477,
0.04168882220983505,
0.05400753766298294,
-0.07393650710582733,
-0.024699563160538673,
-0.058753132820129395,
0.0665164664387703,
0.06986590474843979,
-0.0... |
<p>How could I check if my data e.g. salary is from a continuous exponential distribution in R? </p>
<p>Here is histogram of my sample:</p>
<p><img src="http://i.stack.imgur.com/QlIMT.png" alt="enter image description here"></p>
<p>. Any help will be greatly appreciated!</p> | g22091 | [
0.05518939346075058,
-0.03087918646633625,
-0.0384625643491745,
-0.049235325306653976,
-0.0411713570356369,
-0.030546113848686218,
0.005136463791131973,
0.006688238121569157,
-0.06194726377725601,
0.001060115871950984,
0.021576248109340668,
0.04362068325281143,
0.04032487794756889,
-0.0173... |
<p>Assume I am looking for a normal distribution $\mathcal{N}(\mu,\Sigma)$. For simplicity let's say we only have 2 random variables $x$ and $y$ and a known $\mu=0$.</p>
<p>Is it possible to estimate $\Sigma$ by observing the variance along multiple directions?</p>
<p>For example, I measure the variance $\sigma_1$ al... | g22092 | [
-0.034613147377967834,
-0.04163804650306702,
-0.009830939583480358,
0.009907121770083904,
0.0037819098215550184,
-0.005876624956727028,
0.03633622080087662,
-0.014221876859664917,
-0.01685990020632744,
-0.01392627228051424,
0.010416128672659397,
0.01881631463766098,
0.002548165386542678,
0... |
<p>I would like to conduct some analysis on some biological traits with regression model.
The response variable is continuous. One important independent variable is the SNP information (wildtype, heterozygous, or homozygous). There are different ways to code it.
It can be treated as a nominal or a ordinal variable (lik... | g64105 | [
0.015532223507761955,
-0.053099535405635834,
-0.02803204581141472,
-0.0032697177957743406,
-0.029440496116876602,
-0.002170039340853691,
0.013245532289147377,
0.022361690178513527,
-0.031342677772045135,
-0.018221978098154068,
0.028307663276791573,
0.031974438577890396,
-0.02239936590194702,... |
<p>I am currently attempting to a produce a series of half lives for chemical residues. I can get each individual one fine using non-linear regression to estimate the parameters A and k (from $P=A \times e^{-kt}$).<br>
However I also need the half life for 3 of the residues combined. I am thinking 3 different approache... | g22095 | [
-0.030728349462151527,
-0.10953928530216217,
0.004865921568125486,
-0.035732202231884,
0.011192437261343002,
-0.011636226437985897,
-0.012817497365176678,
0.008138908073306084,
-0.02596820518374443,
0.04584381356835365,
-0.008783946745097637,
-0.014334083534777164,
0.030667133629322052,
0.... |
<p>The problem is separation of multiple normal distributions of fish length, each normal distribution representing a distinct year class contributing to the overall population in a long-lived species. Marian Y Y Yong in 1975 announced a Fortran IV program ENORMSEP in Fishery Bulletin vol. 73 to accomplish this task, ... | g64106 | [
0.0060225180350244045,
-0.006026413291692734,
-0.006788236554712057,
-0.07453221082687378,
-0.05769847333431244,
-0.04047445207834244,
0.045678768306970596,
0.02282840572297573,
-0.027033349499106407,
0.004693841096013784,
0.00975741446018219,
-0.011772248893976212,
0.015586779452860355,
-... |
<p>I have recently begun to look into Bayesian Inference for fisheries. I have some difficulties in playing around with distributions.</p>
<p>This is my model;</p>
<p>\begin{equation} L_t = L_∞*(1-e^{(-K*(t-t_0))})*e^{(ε_t )} \end{equation}</p>
<p>These are my parameters and their priors;</p>
<p>\begin{equation} K... | g64107 | [
0.010811606422066689,
-0.022114045917987823,
0.001627973048016429,
-0.04285315424203873,
0.0058159069158136845,
0.005830089095979929,
0.04278906434774399,
0.0299671683460474,
-0.03339946269989014,
0.03408424183726311,
-0.007182784844189882,
0.03195911645889282,
-0.0030234847217798233,
0.01... |
<p>It is stated here[1] that we can use ROBPCA to detect outliers for multivariate data. After reading the manual ([2] page 12 : "multivariate normal model etc."), I think the ROBPCA method is also designed for outlier detection in normally distributed data, but I need confirmation from someone.</p>
<p>In my case, I h... | g668 | [
0.012678609229624271,
-0.04619893804192543,
0.015482237562537193,
-0.03052016906440258,
-0.03372642397880554,
-0.01535302959382534,
0.07652802765369415,
0.03428521752357483,
-0.01723506487905979,
0.017085609957575798,
0.015757426619529724,
0.04013966768980026,
-0.00813977513462305,
0.00406... |
<p>I know this is basic question, but I have trouble understanding pca.
pca can be used for dimensionality reduction. Let's assume we have 100 features that we think are redundant. After applying pca, we find that 2 principal components explain 90% of the variance. </p>
<ol>
<li>How can we divide the 100 original fea... | g64108 | [
-0.00456172926351428,
-0.025304187089204788,
0.011864378117024899,
-0.08992157876491547,
0.021192517131567,
-0.024718137457966805,
0.08220954239368439,
0.07820382714271545,
-0.05547531694173813,
-0.007847513072192669,
0.0066308993846178055,
0.022970076650381088,
0.007058935705572367,
0.038... |
<p>It is well known that researchers should <a href="/questions/81773/exploratory-data-analysis-vs-null-hypothesis-testing">spend time observing and exploring existing data</a> and research before forming a hypothesis and then collecting data to test that hypothesis (referring to null-hypothesis significance testing). ... | g64109 | [
0.02138388343155384,
-0.0009914934635162354,
0.01958596333861351,
-0.011315522715449333,
0.026504823938012123,
0.01220064889639616,
0.03580665588378906,
-0.011716385371983051,
-0.02731063775718212,
-0.0009146286174654961,
0.02564217336475849,
-0.010638113133609295,
0.04910818114876747,
0.0... |
<p>I have some data stored as a list from some computations. I want to calculate the "distance" the sequence is away from satisfying the central limit theorem.</p>
<p>I would like to know, what should I use as the "distance"? And how do I calculate it?</p>
<p>This is based on a conjecture that the data satisfies the ... | g22096 | [
0.03493209555745125,
0.04243658855557442,
-0.002426739316433668,
-0.025527412071824074,
-0.049922917038202286,
-0.016568228602409363,
-0.02687527984380722,
0.059030283242464066,
-0.06447700411081314,
-0.027887776494026184,
-0.0171111561357975,
0.027629930526018143,
0.0058608101680874825,
-... |
<p>I am trying to make sense of what a saturated model is. AFAIK it's when you have as many features as observations.</p>
<p>Can we say a saturated model is a special-case of an extremely overfitted model? </p> | g64110 | [
-0.002033271361142397,
0.06448908895254135,
-0.016527554020285606,
-0.05544915422797203,
0.022239986807107925,
0.008437051437795162,
0.00774346524849534,
-0.0017772606806829572,
0.010285823605954647,
0.03773007541894913,
-0.036252252757549286,
0.010985095985233784,
0.06794404238462448,
-0.... |
<p>I am analyzing the performance of a predictive model with the AUC, area under the ROC curve. I repeat several times cross-validation, and I have different estimations of the AUC in each folder. For example, I repeat 10 times 10-fold CV and then, I have 100 estimations of AUC where I can calculate the MEAN(AUC) and t... | g64111 | [
0.019355960190296173,
-0.0003689463483169675,
-0.011640451848506927,
-0.03474820405244827,
0.013974341563880444,
-0.01989169232547283,
0.07625619322061539,
-0.011539259925484657,
-0.058800023049116135,
0.015314118005335331,
-0.03852536901831627,
0.030966022983193398,
0.03644787147641182,
-... |
<p>I have been reading a lot about ROC curves, but honestly I still don't have it cleared in my mind. So I request anyone here who could explain me about it with respect to my dummy example below.</p>
<p>So lets say I have a microarray data as follows:</p>
<pre><code>Sites Samp1 Samp2 Samp3 Samp4 Samp5 ... SampN
site... | g64112 | [
0.05302386358380318,
-0.05791280418634415,
0.01809612847864628,
-0.05122526362538338,
0.015979396179318428,
-0.0332084484398365,
0.04483545199036598,
0.008296022191643715,
-0.030576510354876518,
-0.06382586807012558,
-0.020512940362095833,
0.04052538797259331,
0.028449691832065582,
-0.0469... |
<p>I have this model:</p>
<p>$$v_{ij} = 1 - x \beta + \delta_i + e_{ij}$$</p>
<p>where $\delta_i$ is the i-th random effect, $e_{ij}$ is the usual error term. I have obtained the betas and now wish to derive the fitted values. How could I do that? Do i need to calculate them as:</p>
<p>$$ \hat v_{ij} = 1 - x \hat\be... | g22101 | [
-0.010470948182046413,
-0.03264441713690758,
-0.038158711045980453,
-0.05112064257264137,
0.06304068118333817,
0.015465275384485722,
0.020670631900429726,
0.02901006117463112,
-0.02087872102856636,
-0.00573747931048274,
-0.060454078018665314,
0.06821005046367645,
0.014285122975707054,
0.05... |
<p>Can some of you help me with following exercise?</p>
<blockquote>
<p>Provide a procedure to generate realizations of a random variable with
CDF (cumulative distribution function) $Fx(x)$ given by:</p>
<p>$Fx(x)=(x+1)/4$ if $-1<x<0$</p>
<p>$Fx(x)=(x+3)/4$ if $0<=x<1$</p>
</blockquote>
<p... | g22102 | [
0.012857054360210896,
0.008448902517557144,
-0.007523431908339262,
-0.07012440264225006,
-0.0017266565700992942,
-0.022316398099064827,
0.05348466709256172,
0.051708631217479706,
-0.04504643753170967,
-0.0341995544731617,
-0.04029801860451698,
0.0413893386721611,
-0.02779657207429409,
0.00... |
<p>The difference between confidence and prediction intervals has been explained in plain English on Cross Validated:
<a href="http://stats.stackexchange.com/questions/16493/difference-between-confidence-intervals-and-prediction-intervals">Difference between confidence intervals and prediction intervals</a></p>
<p>How... | g22103 | [
0.03251270204782486,
-0.04076585918664932,
-0.0003161173372063786,
-0.00817613210529089,
-0.02845683880150318,
0.026953300461173058,
0.007701162248849869,
0.052466634660959244,
-0.018529163673520088,
-0.012172547169029713,
0.020785611122846603,
0.04578808695077896,
0.011979547329246998,
-0... |
<p>Let $\{x_1,\ldots,x_N\}$ be observations drawn from an unknown (but certainly asymmetric) probability distribution.</p>
<p>I would like to find the probability distribution by using the KDE approach:
$$
\hat{f}(x) = \frac{1}{Nh}\sum_{i=1}^{N} K\bigl(\frac{x-x_i}{h}\bigr)
$$
However, I tried to use a Gaussian kernel... | g64113 | [
-0.010620273649692535,
0.018225127831101418,
-0.037668049335479736,
-0.03535209223628044,
0.008354275487363338,
-0.002499709604308009,
-0.021635068580508232,
0.0013111771550029516,
-0.03393185883760452,
0.0007057077018544078,
0.03449590504169464,
-0.008239523507654667,
0.09713226556777954,
... |
<p>I'm analyzing the change of various psychometric features that are supposed to change during treatment and their relation to some other features (I don't think I have to go much into detail here). My dataset contains two waves of measurement on treated subjects (before and after treatment). Due to attrition, I handl... | g64114 | [
0.026965158060193062,
-0.07822839170694351,
-0.022269979119300842,
-0.06387181580066681,
0.002698139986023307,
0.013541897758841515,
0.017224902287125587,
0.05614997446537018,
-0.0011060317046940327,
0.010662969201803207,
0.016135554760694504,
-0.0000659148208796978,
0.014228036627173424,
... |
<p>I have total 19 banks with five years data, comprising 95 observations total. I have 5 independent variables and 1 dependent variable. Can i apply multiple regression analysis by taking all five years data at once or I have to apply multiple regression for each year separately? </p> | g64115 | [
0.020677777007222176,
-0.0010522222146391869,
0.024064119905233383,
-0.015898101031780243,
-0.04898820072412491,
-0.0019044831860810518,
0.055978212505578995,
0.03529301658272743,
-0.01815064437687397,
-0.009121648967266083,
-0.019635280594229698,
-0.02463226579129696,
-0.03587501868605614,
... |
<p>I am trying to apply ADT as a distance between two images or their DCT coefficents. The ADT is given as (image taken from "Bidirectional PCA with assembled matrix distance metric for image recognition - Wangmeng Zuo ; Zhang, D. ; Kuanquan Wang":</p>
<p><img src="http://i.stack.imgur.com/379Qk.png" alt="enter image ... | g22105 | [
0.023598521947860718,
-0.023256372660398483,
-0.006508226506412029,
-0.06831709295511246,
0.007932765409350395,
-0.03236053138971329,
-0.002197232795879245,
0.060924287885427475,
-0.043315351009368896,
-0.015914876013994217,
0.02919047325849533,
0.04134826734662056,
0.07323485612869263,
-0... |
<p>I have a family of models that give me a forecast distribution for the next observation in a time series. So given observations $O_1, \dots, O_T$, I can calibrate the model and get a distribution for $O_{T+1}$. My observations are continuous random variables. How can I check which model provides the best forecast fo... | g64116 | [
-0.0009461691952310503,
-0.04817751422524452,
-0.011190403252840042,
-0.026265211403369904,
0.007113300263881683,
-0.011314701288938522,
0.008842278271913528,
0.0064178998582065105,
-0.0701826885342598,
-0.015029847621917725,
0.01839831843972206,
0.003939834889024496,
0.09012989699840546,
... |
<p>I am studying my lecture notes where I saw this:</p>
<p>$Y_t=Y_{t-1} +u_t$ </p>
<p>$Y_t=0.5* Y_{t-1} +u_t$ </p>
<p>$y_t=0.8* u_{t-1}+u_t$</p>
<p>The first two models are AR(1) and the third one is an MA(1) model. </p>
<p>In the first model where $\beta$ is 1, the difference between today's value and yesterday's... | g64117 | [
0.004758395720273256,
-0.02995637059211731,
0.00811243150383234,
0.009989295154809952,
0.06298613548278809,
0.019619958475232124,
0.053965166211128235,
-0.007162656635046005,
-0.058784693479537964,
0.029040904715657234,
0.03830317407846451,
-0.012476425617933273,
0.06073017790913582,
0.029... |
<p>The figure below (Figure 1 from p. 646 of <a href="http://www.researchgate.net/profile/Francisco_Botella2/publication/227733110_An_empirical_demonstration_of_the_ideal_free_distribution_Little_Grebes_Tachybaptus_ruficollis_breeding_in_intensive_agricultural_landscapes/file/79e41509bc854702ac.pdf" rel="nofollow">this... | g64118 | [
0.018569737672805786,
-0.029362693428993225,
0.0000559847176191397,
-0.08307512104511261,
0.00002761828545772005,
-0.04933138191699982,
-0.012057822197675705,
0.01110899168998003,
-0.05020090192556381,
-0.007997069507837296,
-0.03893527388572693,
0.00876555684953928,
-0.009058498777449131,
... |
<p>I'm struggling with two exercises for which I do possess answers, but I have no idea why they would be like that. I haven't done any statistics in a long time (restarting studies).</p>
<p><strong>Question 1</strong></p>
<p>Two buddies agreed to come to a meeting between 1 pm and 2 pm. Each one will come at random ... | g64119 | [
0.03355269879102707,
-0.025886008515954018,
-0.01438629999756813,
0.01572916842997074,
-0.008810059167444706,
0.00765257840976119,
0.0259531382471323,
-0.009218808263540268,
-0.03228919208049774,
0.023446381092071533,
-0.00854989793151617,
0.022765975445508957,
-0.03037680685520172,
0.0004... |
<p>R doesn't return the correlation coefficient's variance (or standard error) when coding <code>summary(linmod)</code>, <code>linmod</code> being a linear model with one stochastic variable. Wouldn't it be reasonable to first check this variance when reflecting on how reliable <code>linmod</code> is in terms of correl... | g22108 | [
0.030186902731657028,
-0.013247299939393997,
-0.006397393997758627,
-0.018960703164339066,
0.023691805079579353,
0.012616289779543877,
0.014008644036948681,
-0.022041598334908485,
-0.018571928143501282,
-0.021360667422413826,
-0.005320069380104542,
0.04975526034832001,
-0.034744612872600555,... |
<p>I am working on fitting distributions to financial data using different volatility models. The simplest case of a gaussian distribution I do understand:
The data is $\mathcal{N}$$(\mu,\sigma^2)$ distributed. So at each day I use a certain amount of data to estimate the $\mu$ and the $\sigma$. If I apply the "normal"... | g22110 | [
0.02044871263206005,
-0.05355457216501236,
-0.01907767355442047,
-0.016177447512745857,
-0.006759029813110828,
0.0012783263809978962,
0.004703936167061329,
-0.025517607107758522,
-0.040879879146814346,
-0.03181225433945656,
-0.006459193304181099,
-0.010015023872256279,
0.052069272845983505,
... |
<p>My panel regression model is as follows: </p>
<p>$$Y_{it}= PS_{it}+PF_{it}+EF_{it}+ e_{it}$$ </p>
<p>where </p>
<p>$i$ : country<br>
$t$ : year<br>
$Y_{it}$ : GDP per capita<br>
$PS_{it}$ : Political stability<br>
$PF_{it}$ : Political Freedom<br>
$EF_{it}$ : Economic Freedom<br>
$e_{it}$ : error term </p>
<p... | g41597 | [
0.04651864990592003,
0.04396587982773781,
-0.01017910148948431,
-0.0019805580377578735,
0.05974245071411133,
-0.006576621904969215,
0.02283167652785778,
0.003177996026352048,
-0.03987845778465271,
-0.010250118561089039,
0.012357138097286224,
0.024605825543403625,
0.005064629949629307,
0.01... |
<p>I have read a few posts on related topics but can't seem to figure out which test would best apply in my study. What I have is ordinal data from the same questions taken at two points(W1 and W2). After the initial rating W1 respondents were exposed to an article (A) and instructed to give ratings to the same questio... | g64120 | [
-0.016945188865065575,
-0.05385920777916908,
-0.019280891865491867,
-0.027112066745758057,
0.017205296084284782,
-0.03256182372570038,
0.032708119601011276,
-0.026756398379802704,
-0.05921643227338791,
-0.013736165128648281,
0.04927154257893562,
0.009254200384020805,
0.017286719754338264,
... |
<p>I'm working from <a href="http://stats.stackexchange.com/questions/31948/looking-for-a-step-through-an-example-of-a-factor-analysis-on-dichotomous-data/32136#32136">caracal's great example</a> conducting a factor analysis on dichotomous data using R and I'm now struggling to understand the difference between <em>VSS... | g47325 | [
0.02244419790804386,
-0.03401768207550049,
-0.01501275971531868,
-0.014682975597679615,
-0.026340162381529808,
-0.07066547870635986,
0.08032578229904175,
0.023863304406404495,
-0.02754136361181736,
-0.017601992934942245,
-0.02333053946495056,
-0.02917562425136566,
0.09196975082159042,
-0.0... |
<p>Suppose we have a $n$ pairs of mutually independent variables over $k$ outcomes and take a mixture distribution, what can we say about mutual information in the mixture? In particular I'm wondering about the upper bound on the mutual information. When $n=1$, the upper bound is $0$, and when $n=k^2$, the upper bound ... | g64121 | [
-0.03125566244125366,
-0.010662239976227283,
-0.003767899703234434,
0.006783727556467056,
-0.026356298476457596,
0.016249574720859528,
-0.048566605895757675,
0.0020565635059028864,
-0.054730262607336044,
-0.009468123316764832,
-0.0074725584127008915,
-0.011808043345808983,
0.0069286325015127... |
<p>is there any possibility to iterate over the tokens of a text document within RapidMiner? My first try was to window the document after tokenisation. But this seems very complicated.</p>
<p>I'm doing this to simulate the creation of a language model like Katz Backoff and so on. Maybe there is a better way to produc... | g64122 | [
-0.0010334306862205267,
-0.012066936120390892,
-0.002978922799229622,
-0.037141103297472,
0.02640789933502674,
-0.0800042450428009,
-0.01426438894122839,
0.023109035566449165,
-0.12396393716335297,
0.02280459739267826,
0.009901169687509537,
0.044683340936899185,
0.014644360169768333,
0.008... |
<p>If two wide-sense stationary processes $X(t)$ and $Y(t)$ are uncorrelated, then the cross correlation is</p>
<p>$R_{XY}(t_1,t_2) = E\{X(t_1)Y(t_2)\} = E\{X(t_1)\}E\{Y(t_2)\}$,</p>
<p>which will be a constant, since $E\{X(t_1)\}$ and $E\{Y(t_2)\}$ are constant. But my question is what conclusion about $R_{XY}(t_1,t... | g64123 | [
0.048539597541093826,
-0.06715432554483414,
-0.003929681144654751,
-0.030223751440644264,
0.010056557133793831,
0.008115042932331562,
0.0808885246515274,
-0.02095082961022854,
-0.00048575628898106515,
0.012663680128753185,
0.0036828976590186357,
-0.0075410413555800915,
-0.03265661001205444,
... |
<p>I have two vectors $x,y \in \mathbb{R}.$ Based on the count and vector length I can compute $p(x)$ and $p(y)$ but I have no information on the joint density. How can I calculate mutual information in this case?</p> | g41600 | [
0.04308294132351875,
0.0020585027523338795,
-0.020082684233784676,
0.021535737439990044,
-0.03224591910839081,
-0.004675222095102072,
-0.009228868409991264,
-0.017793981358408928,
-0.07026220858097076,
0.0010655265068635345,
-0.0038300480227917433,
-0.02306234836578369,
0.009554977528750896,... |
<p>I would like to perform a $\chi^2$ hypotheses test for association based on a $2 \times 2$ contingency table. However, my contingency table</p>
<p>$$
\begin{array}{|c|c|}
\hline \\
a & b \\
\hline \\
c & d \\
\hline
\end{array}
$$</p>
<p>does not contain integer count data but probabilities</p>
... | g22117 | [
0.05265079066157341,
-0.005898995324969292,
-0.011687934398651123,
-0.00032708782237023115,
0.004300758242607117,
-0.05678056925535202,
0.02822052501142025,
0.009684048593044281,
-0.028540801256895065,
-0.03243047744035721,
-0.021690376102924347,
0.01815236732363701,
0.0021714011672884226,
... |
<p>What are the appropriate uses for a grouped vs a stacked bar plot?</p> | g41602 | [
-0.03326479345560074,
0.042622894048690796,
0.0027503424789756536,
-0.03900929540395737,
-0.021850338205695152,
-0.042533572763204575,
0.03525331988930702,
-0.003136642277240753,
-0.045685552060604095,
-0.03448326140642166,
0.06210038438439369,
0.024300888180732727,
0.009690597653388977,
0... |
<p><a href="http://en.wikipedia.org/wiki/Deming_regression" rel="nofollow">Deming Regression</a> is a regression technique taking into account uncertainty in both the explanatory and dependent variable.</p>
<p>Although I have found some interesting references on the calculation of this property in <a href="http://iops... | g64124 | [
0.008052359335124493,
-0.017013441771268845,
-0.013410920277237892,
-0.03496593236923218,
0.002095684874802828,
-0.027515100315213203,
0.06005353108048439,
0.04857759177684784,
-0.052220847457647324,
-0.05355202034115791,
-0.009965652599930763,
0.04062153398990631,
0.04046189412474632,
0.0... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.