question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Suppose I observe a random variable $x$ drawn from a non-central t- or F- distribution, and would like to perform inference on the non-centrality parameter. How would a Bayesian approach this problem? Are there known conjugate priors for these? </p>
<p>For the t-distribution I have seen some reference to LeCoutre's... | g36011 | [
0.015133260749280453,
0.003154564881697297,
-0.0005295869777910411,
-0.1446596086025238,
-0.007248971611261368,
-0.04873860254883766,
-0.020093321800231934,
0.030641799792647362,
-0.06223340705037117,
-0.04735420271754265,
0.002176555572077632,
0.01257358118891716,
0.04226143658161163,
0.0... |
<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/23417/dynamic-recommender-systems">Dynamic recommender systems</a> </p>
</blockquote>
<p>A <a href="http://en.wikipedia.org/wiki/Recommender_system" rel="nofollow">Recommender System</a> would measure the ... | g49668 | [
-0.013888716697692871,
-0.014736523851752281,
-0.003300989978015423,
0.016607197001576424,
-0.00798176508396864,
0.014630706049501896,
0.0037001706659793854,
-0.03184567019343376,
-0.037333328276872635,
0.002948300912976265,
0.05511321499943733,
0.03476822003722191,
0.044669028371572495,
0... |
<p>I used ASreml to estimate genetic parameters for feed intake using bivariate and multivariate models. </p>
<p>However, I am very confused about how to define variance structures (even though I went through the "Users Guide" many times). Is there a quick way to check which models will be used in the R and G structur... | g66147 | [
0.0004386832006275654,
-0.04141808673739433,
-0.012544740922749043,
0.004601484630256891,
0.015773214399814606,
-0.03288650140166283,
0.02563016675412655,
-0.003869974287226796,
-0.08142945170402527,
0.013538138009607792,
0.00954851508140564,
0.0024348439183086157,
0.052770331501960754,
0.... |
<p>Just trying to see if my reasoning is correct....</p>
<p>If the probability that next saturday will rain is 0.25 and the probability that next sunday will rain is 0.25, what is the probability that during the weekend will rain?</p>
<p>Assuming that A and B are independent events,</p>
<p>P(A∪B)=P(A)+P(B)-P(A∩B)</p... | g25049 | [
0.026709025725722313,
0.004322970751672983,
0.021901967003941536,
-0.053790003061294556,
-0.019707147032022476,
-0.004106378182768822,
0.014330229721963406,
0.00859021581709385,
-0.0335407480597496,
-0.002218944253399968,
-0.04355902969837189,
0.009738006629049778,
0.0011777831241488457,
-... |
<p>I am trying to find the expected value of $Z$ where $Z = Y\cdot e^X$ where $Y \sim U(0,1)$ and $X \sim U(0,1)$.</p>
<p>My attempt so far:</p>
<p>$$F_Z(z) = P(Ye^X \le z) = \int \int_{Ye^X \le z} f(x,y)\, dxdy$$</p>
<p>Where $f_{X,Y}(x,y) = f_y\cdot f_{e^x}$</p>
<p>$$f_Y(y) = \frac{1}{1-0}\,, \quad y \in (0,1)$$... | g66148 | [
-0.023928595706820488,
-0.007932591252028942,
-0.0368034727871418,
-0.013694477267563343,
0.013067400082945824,
-0.06304537504911423,
0.022710999473929405,
0.010216695256531239,
-0.012838173657655716,
-0.04516226053237915,
-0.030112499371170998,
0.03432011231780052,
0.04047195240855217,
-0... |
<p>So the title is a bit vague, but I am trying to solve some basic probability inequality. Given that $P(B\cap C) > P(B)P(C)$, how can I show that $P(B|C) > P(B|W\setminus C)$?</p>
<p>I started by showing that $P(B|C) > P(B)$, but I am not sure if this helps. Thoughts?</p>
<p>Thanks.</p> | g758 | [
0.0024063417222350836,
0.02906595543026924,
-0.005656412336975336,
0.004927206318825483,
0.036135684698820114,
-0.010634436272084713,
-0.015378812327980995,
0.0030922703444957733,
-0.036886587738990784,
0.034718651324510574,
-0.008279120549559593,
0.07983260601758957,
-0.02864314615726471,
... |
<p><img src="http://i.stack.imgur.com/YwgCn.jpg" alt="enter image description here"></p>
<p>So I have this directed graph (above)</p>
<p>Each arrow represents a causal link. Is it possible to calculate the affect of X on Z, where all variables are observed except U and W. If so, what would the regression equation(s) ... | g66149 | [
0.01088704913854599,
-0.058760277926921844,
-0.04225732013583183,
-0.029921308159828186,
0.006277244072407484,
-0.0655122771859169,
0.0806480273604393,
0.05987831950187683,
0.010653555393218994,
-0.07423092424869537,
0.009053953923285007,
0.10380895435810089,
0.06779874861240387,
0.0088496... |
<p><img src="http://i.stack.imgur.com/UQ88F.jpg" alt="enter image description here"></p>
<p>Given this chart, how do you determine the slope of the regression Y on F? </p> | g66150 | [
0.02887718193233013,
-0.004150263499468565,
-0.021726170554757118,
-0.0034108359832316637,
0.05967649444937706,
-0.041129037737846375,
0.04924435541033745,
0.000245188653934747,
-0.019056834280490875,
-0.0823579952120781,
-0.04122944548726082,
0.001217157463543117,
0.051379188895225525,
0.... |
<p>In a mixed effect model where the intercept is random effect and the slope is fixed effect (see the code below), I understand the output of <code>summary(glmer(...))</code>. But I do not understand <code>coef(glmer(...))</code>; it will output the intercept for each sample. In the example, how are those 100 intercep... | g66151 | [
-0.010369119234383106,
-0.059167295694351196,
-0.009158879518508911,
-0.021188151091337204,
0.05394716560840607,
-0.014687387272715569,
0.12078500539064407,
0.03248859569430351,
-0.046002600342035294,
-0.01349287573248148,
-0.06106741353869438,
0.018166059628129005,
0.042344652116298676,
0... |
<p>I have two predictors (X1 and X2) with large Beta's and large predictor-independent variable correlations (say it is like rs). In addition, I have another variable (X3; Beta=0.17; rs=0.18) which was not statistically significant in predicting the scores in the dependent variable. Last, I have an X4 with zero Beta an... | g25054 | [
0.006385449785739183,
-0.009012979455292225,
0.020136840641498566,
-0.013274144381284714,
-0.004266044590622187,
0.015982862561941147,
0.03552551567554474,
0.03280975669622421,
-0.0363820381462574,
-0.05541355535387993,
0.02272072806954384,
0.018335003405809402,
-0.00678812712430954,
-0.00... |
<p>I have a question:</p>
<blockquote>
<p>Is the ROC curve enough to assess goodness of fit? Or do you need other tests?</p>
</blockquote> | g45270 | [
0.04655064269900322,
0.008142228238284588,
0.02012309990823269,
-0.0030990096274763346,
0.04219115152955055,
-0.03672054037451744,
0.018722573295235634,
0.032579656690359116,
0.0019819880835711956,
-0.026966841891407967,
-0.024946032091975212,
0.002386637730523944,
-0.024757077917456627,
-... |
<p>I am trying to obtain the standard errors of my maximum likelihood model, I am having trouble to fix the error message: </p>
<pre><code>**Error in optim(c(0.02, 1.75, 124, 1.5, 0.85), logA, gr = NULL, method = "Nelder-Mead", :
non-finite finite-difference value [1]**
</code></pre>
<p>The code I have so far is ... | g66152 | [
-0.015485141426324844,
-0.06988794356584549,
0.010841057635843754,
-0.047535695135593414,
0.024024683982133865,
-0.061555810272693634,
0.06310639530420303,
-0.00513775460422039,
-0.07134391367435455,
-0.007822182029485703,
-0.01875072531402111,
0.037915848195552826,
0.04891166090965271,
0.... |
<p>Suppose we have a variable $x$ with 3 levels (e.g. $x_1, x_2$ and $x_3$). We want to see if there is an interaction between $x$ and $y$ where $y$ is a continuous variable. To test this would we include the following terms: $x_{1}y, x_{2}y, x_{3}y$ in a regression model? </p> | g66153 | [
0.03591879457235336,
-0.005758413579314947,
-0.022076338529586792,
-0.014594771899282932,
0.01835242472589016,
-0.004848232958465815,
0.009696087799966335,
-0.028042949736118317,
-0.0343623086810112,
0.001977413659915328,
-0.020955335348844528,
0.026085831224918365,
-0.055213503539562225,
... |
<p>I am working on a data set of about 34K rows trying to predict an ordinal response variable using R. I have tried association rules, random forest and ordinal regression. Does anyone have experience with other algorithms which are worth a try?</p> | g66154 | [
0.0029989639297127724,
-0.013022324070334435,
0.0049921865575015545,
-0.06129574403166771,
-0.04372522979974747,
-0.07968931645154953,
0.01110987737774849,
-0.01965482532978058,
0.009616374969482422,
0.016634533181786537,
0.0481954850256443,
0.0001922671071952209,
0.02516288124024868,
-0.0... |
<p>What is your favorite free tool on Linux for multivariate logistic regression?</p>
<p>Possibilities I've seen:</p>
<ul>
<li><a href="http://www.r-project.org" rel="nofollow">R</a> (see <a href="http://nlp.stanford.edu/~manning/courses/ling289/logistic.pdf" rel="nofollow">paper</a>). <a href="http://stackoverflow.... | g25056 | [
0.014761148951947689,
0.0003318322997074574,
0.0033358449582010508,
-0.018018439412117004,
-0.041371289640665054,
-0.09741681814193726,
-0.06062524765729904,
-0.016917657107114792,
-0.079283207654953,
-0.05866779759526253,
0.06651715189218521,
-0.013142646290361881,
0.1264725625514984,
-0.... |
<p>What modern tools (Windows-based) do you suggest for modeling financial time series?</p> | g66155 | [
0.00892445258796215,
-0.014182530343532562,
-0.0136726638302207,
0.0036449336912482977,
-0.034910425543785095,
-0.06754037737846375,
0.026031335815787315,
-0.033570289611816406,
-0.07413537800312042,
-0.019499540328979492,
0.05007517710328102,
-0.010623862035572529,
0.04073048755526543,
0.... |
<p>What is a standard deviation, how is it calculated and what is its use in statistics?</p> | g49330 | [
0.04002746194601059,
0.007219518069177866,
-0.025031039491295815,
-0.010906526818871498,
-0.018843036144971848,
0.02934332750737667,
0.014422209933400154,
0.04155340418219566,
0.002167197410017252,
-0.07082153111696243,
-0.00865959096699953,
-0.04086582362651825,
0.0459061861038208,
-0.046... |
<p>I'm a little confused about the analysis of normality in a repeated measures ANOVA I'm doing. It's a factorial ANOVA with three rm IVs each of which has only 2 levels. I've read in a few places online and in a book or two that to assess normality in a repeated measures ANOVA, I look at the distributions within each ... | g66156 | [
-0.023548336699604988,
-0.0019243828719481826,
0.004671779461205006,
0.003927957266569138,
-0.03001912496984005,
-0.01146929245442152,
0.048234108835458755,
0.024938087910413742,
-0.005187463480979204,
-0.0067196134477853775,
-0.041046373546123505,
0.034080956131219864,
-0.04757107421755791,... |
<p>What are some of the ways to forecast demographic census with some validation and calibration techniques?</p>
<p>Some of the concerns:</p>
<ul>
<li>Census blocks vary in sizes as rural
areas are a lot larger than condensed
urban areas. Is there a need to account for the area size difference?</li>
<li>if let's say ... | g25060 | [
0.03771102800965309,
-0.009215283207595348,
0.009939937852323055,
0.03493838012218475,
-0.04721754416823387,
0.011066198348999023,
-0.011097569018602371,
0.021624373272061348,
0.010721741244196892,
-0.012251955457031727,
0.035413485020399094,
-0.026762766763567924,
0.10372446477413177,
0.0... |
<p>How would you describe in plain English the characteristics that distinguish Bayesian from Frequentist reasoning?</p> | g49285 | [
0.057823296636343,
0.021994803100824356,
-0.0075178733095526695,
-0.009873630478978157,
0.018078623339533806,
-0.037726446986198425,
0.03142097592353821,
0.011766585521399975,
0.0007865781662985682,
-0.0386589840054512,
0.044020384550094604,
-0.012172785587608814,
0.0345560647547245,
0.058... |
<p>How can I find the PDF (probability density function) of a distribution given the CDF (cumulative distribution function)?</p> | g66157 | [
0.0421891026198864,
-0.014949425123631954,
0.009562887251377106,
-0.0648035928606987,
-0.0015276813646778464,
-0.011200501583516598,
0.005959942936897278,
0.032231081277132034,
-0.04650970175862312,
-0.05197819694876671,
0.0027476693503558636,
-0.04075426608324051,
0.06093166768550873,
-0.... |
<p>I'm reading a Scientific paper on image classification. In the experimental results they speak of top-1 and top-5 accuracy but i've never heard of the term, nor can find it using google.</p>
<p>Can someone give me a definition or point me somewhere? :)</p> | g16861 | [
0.010826586745679379,
-0.03609095886349678,
-0.013501600362360477,
-0.027554865926504135,
0.012908796779811382,
-0.014832285232841969,
0.041142646223306656,
0.01073976419866085,
-0.06750986725091934,
-0.01696735806763172,
-0.01675574854016304,
0.021914036944508553,
0.03626511991024017,
-0.... |
<p>For a model with a binomial proportion as response variable, which is fitted with according to a binomial distribution, a dispersion parameter $\phi$ can be calculated, which is equal to the sum of the squared Pearson residuals divided by the residual degrees of freedom.</p>
<p>I was following along with <a href="h... | g45280 | [
0.039996013045310974,
-0.04736820235848427,
-0.007388623431324959,
-0.03165511414408684,
0.05021511763334274,
0.004716324619948864,
0.04375283047556877,
-0.051684100180864334,
-0.04360058531165123,
0.002618219004943967,
-0.06096821278333664,
-0.012353026308119297,
-0.0012436209945008159,
-... |
<p>I have an original data set with a number of features N equal to 135 and a number of rows equal to 32000. The last column of the data set ( column 136 ) can take either -1 or 1 depending on the class of the row. Each of the features can take a binary value of 0 or 1 ( characteristic present or not).</p>
<p>The orig... | g66158 | [
0.018389934673905373,
0.0007248573238030076,
0.010826039128005505,
-0.033055149018764496,
-0.019228018820285797,
-0.06123078987002373,
0.08167248964309692,
0.0724644660949707,
-0.06338387727737427,
-0.0431828647851944,
-0.014780002646148205,
0.05222289636731148,
0.027854567393660545,
0.050... |
<p>It is often stated that the square of the sample correlation $r^2$ is equivalent to the $R^2$ coefficient of determination for simple linear regression. I have been unable to demonstrate this myself and would appreciate a full proof of this fact.</p> | g66159 | [
0.06035662814974785,
-0.046643588691949844,
0.014806863851845264,
-0.015278849750757217,
0.03317190334200859,
-0.02717350795865059,
0.04868460074067116,
-0.005205466877669096,
-0.00947675108909607,
-0.03667907044291496,
-0.030103692784905434,
0.03594699129462242,
0.0036726028192788363,
-0.... |
<p>Would anyone please give me a simple explanation of how can I read the results of the decision tree in R? My target attribute (label) have 12 different labels. Thanks!!</p>
<pre><code>> printcp(fittree) # display the results
Classification tree:
rpart(formula = bucket ~ txamountunit, method = "class")
Variable... | g66160 | [
-0.033841002732515335,
-0.04184974730014801,
0.025239063426852226,
-0.03825440630316734,
0.04051119089126587,
-0.03450892120599747,
0.009982804767787457,
0.03570371866226196,
-0.03558359667658806,
0.02220849320292473,
0.01801324263215065,
0.03691192343831062,
0.05389459803700447,
-0.016693... |
<p>When do Metropolis sampling or MCMC, we need a target distribution $P_{target}(\theta)$, and a proposal distribution $P_{proposal}(\theta)$, then a value $\theta_i$ is generated via $P_{proposal}(\theta)$, we need to compute the probability whether to accept or reject this $\theta_i$ via $P_{target}(\theta)$, right?... | g66161 | [
0.0006935400306247175,
0.002535046311095357,
0.0005632027750834823,
-0.054025210440158844,
-0.03457469120621681,
0.021748818457126617,
-0.010922682471573353,
0.07925822585821152,
-0.054966431111097336,
-0.021202748641371727,
0.02289610356092453,
0.03794202581048012,
0.017450343817472458,
0... |
<p>I used height, weight, gender and age to regress on BMR (basal metabolic rate) and obtained the following qq plot of residuals<img src="http://i.stack.imgur.com/m8bMS.jpg" alt="enter image description here"></p>
<p>I then regressed the above variables with log BMR and obtained the following qq plot for residuals<im... | g66162 | [
0.044778820127248764,
-0.033282872289419174,
-0.0023053877521306276,
-0.00530958641320467,
-0.01591559126973152,
-0.010269506834447384,
0.033909834921360016,
-0.0013351532397791743,
-0.0539095476269722,
-0.04590097442269325,
-0.004006912931799889,
0.054903529584407806,
0.0349428616464138,
... |
<p>If the magnitude of covariance doesn't really convey any reliable information, and correlation provides us the same information but also gives the degree of dependence, then why use covariance at all ? </p> | g25068 | [
0.03283637389540672,
0.0013093396555632353,
0.01297381054610014,
-0.04538039118051529,
-0.018221639096736908,
0.06577182561159134,
0.024637902155518532,
0.00536869652569294,
-0.02665073610842228,
-0.03889942169189453,
0.037045709788799286,
-0.028535014018416405,
-0.005400830414146185,
0.00... |
<p>I have two questions about structural equations modeling: </p>
<ol>
<li>To perform comparisons of model estimates for different groups (3 clusters), do I always have to analize measurement invariance first? </li>
<li>If the answer to #1 is yes, how can I do that with SmartPLS?</li>
</ol> | g66163 | [
-0.016072193160653114,
-0.039664529263973236,
-0.025927118957042694,
-0.012825923971831799,
0.03431360051035881,
-0.0169998649507761,
0.013489749282598495,
0.013171667233109474,
-0.01460134144872427,
-0.008523688651621342,
-0.010010774247348309,
-0.003315625712275505,
-0.014197695069015026,
... |
<p>Assume one has the posterior distribution of a parameter, $p(\theta|y)$ and what I mean by having it is that for each point of $\theta$, one can use Monte Carlo method+MCMC to calculate the $p(\theta|y)$. Now my question is if I want to sample from $p(\theta|y)$, them basically I have to do one Gibbs sampling(for ex... | g66164 | [
0.03520090878009796,
-0.0024044218007475138,
0.0063272202387452126,
-0.04088149219751358,
-0.005736420396715403,
-0.004959131591022015,
0.0046235485933721066,
0.023233884945511818,
-0.00584754953160882,
0.010392853990197182,
-0.02688736654818058,
0.04025399312376976,
0.03131305053830147,
0... |
<p>Let's say I have a set of i.i.d. samples $X_1,\ldots,X_N \sim N_p(\mu, \Sigma)$. Now define
\begin{equation}
d^2_i(b)=(X_i - b)'\Sigma^{-1}(X_i-b)
\end{equation}
which is essentially the Mahalanobis distance, except that it measures the distance from $X_i$ to $b$ (with respect to the principal component axes), rathe... | g49475 | [
-0.006713682785630226,
-0.0032324453350156546,
-0.02721843309700489,
-0.0375550352036953,
-0.015811603516340256,
-0.05505964905023575,
0.04353808984160423,
0.004254820290952921,
-0.05249583348631859,
0.017415616661310196,
-0.028042227029800415,
0.0662146657705307,
-0.00307493400759995,
-0.... |
<p>I am somewhat confused about lifetime risk. The National Kidney Federation released data saying that the lifetime risk of a white American male needing dialysis was around 3%. However, considerably less than 1% of the population actually are on dialysis... why the discrepancy? Why aren't 3% of American males on dial... | g66165 | [
0.0005420281086117029,
0.04973982647061348,
0.0023754609283059835,
0.034988075494766235,
-0.005534250754863024,
0.0489283911883831,
-0.015805792063474655,
0.04277407377958298,
0.022720467299222946,
0.0002430667809676379,
0.007661676034331322,
0.013182524591684341,
0.04091733321547508,
-0.0... |
<p>I need to study the effect of certain drug (e.g. drug1) intake on blood levels (e.g. white blood cells). I have 900 observations with data on drug1 (with yes or no); and numeric measurements for the white blood levels) What statistical model would be apt for such analysis and for graphical representation.</p>
<p>Th... | g66166 | [
-0.017123688012361526,
0.04306406155228615,
-0.011392071843147278,
-0.008469419553875923,
0.01467003021389246,
-0.05340178310871124,
0.036952175199985504,
0.017401427030563354,
-0.030371922999620438,
0.012726876884698868,
0.0445682518184185,
0.02042962610721588,
0.07040257751941681,
0.0535... |
<p>I am analysing a model which has 5 constructs. Each construct has 3 Likert scale questions. For instance, I want to analyse the relationship and effect of the construct "PERCEIVED USEFULNESS" which is the independent variable upon the construct "BEHAVIOURAL INTENTION" which is the dependent variable. Both constructs... | g66167 | [
-0.02235262654721737,
-0.06326615065336227,
0.008593999780714512,
-0.06880493462085724,
0.0280209481716156,
0.0003069931117352098,
0.011514517478644848,
0.009715997613966465,
-0.02519807033240795,
-0.03022889792919159,
0.00254545034840703,
-0.021343903616070747,
0.013826515525579453,
0.019... |
<p>I am aware that you must be careful about when you can compare effect sizes. But let's assume that I have two effect sizes from two similar studies: similar groups, same intervention, same measurement. Let's say, two classes in the same school receiving the same intervention and measured on the same outcome. If o... | g66168 | [
-0.009953619912266731,
0.018455050885677338,
0.012678309343755245,
-0.10371741652488708,
-0.014211137779057026,
-0.03680219128727913,
0.002248029923066497,
-0.024725329130887985,
-0.024308880791068077,
-0.03448908403515816,
0.03754279017448425,
0.02395690232515335,
0.03270413354039192,
0.0... |
<p>On Larry Wasserman's blog, he talks about the "Steep price of sparsity" here:</p>
<p><a href="http://normaldeviate.wordpress.com/2013/07/27/the-steep-price-of-sparsity/" rel="nofollow">http://normaldeviate.wordpress.com/2013/07/27/the-steep-price-of-sparsity/</a></p>
<p>In it, he points out that a sparse estimatio... | g66169 | [
0.057222116738557816,
-0.0055594970472157,
-0.017611369490623474,
-0.01241405587643385,
0.0467643104493618,
-0.03618001937866211,
0.05898459255695343,
0.02157563529908657,
-0.0271249171346426,
0.02519231289625168,
-0.06633360683917999,
0.039138585329055786,
0.03835045546293259,
0.039507661... |
<p><strong>English</strong> following dutch</p>
<p>In mijn afstandmaat voor mengelingen van variabele mag ik alleen een combinatie van continue en ordinale variabele gebruiken. Mijn data bestaat echter uit een mengeling van ordinale, nominale en continue variabele. Mag ik aannemen dat al mijn nominale variabele ook or... | g45294 | [
0.04403899610042572,
-0.046332962810993195,
0.008665707893669605,
-0.05922933667898178,
-0.028071457520127296,
-0.007392648607492447,
-0.015518018044531345,
-0.013073385693132877,
-0.009357675909996033,
-0.018179994076490402,
0.025480957701802254,
0.023664386942982674,
-0.0033384556882083416... |
<p>Here's a Q-Q plot for my sample (notice the logarithmic Y axis); $n = 1000$:</p>
<p><img src="http://i.stack.imgur.com/QlMGU.png" alt="enter image description here"><br>
As pointed out by whuber, this indicates that the underlying distribution is left-skewed (the right tail is shorter).</p>
<p>Using <code>shapiro.... | g25073 | [
0.0071891783736646175,
-0.044833507388830185,
-0.014860409311950207,
0.0064112357795238495,
-0.0448370985686779,
0.04968539625406265,
0.00995586346834898,
-0.0012133551063016057,
-0.04436205327510834,
0.004436229821294546,
0.01345224678516388,
0.0422859713435173,
0.04541861638426781,
-0.01... |
<p>I want to know if this is a reasonable approach. I conducted the same experiment on two different species with small sample sizes (7-25 per species) in 4 years at 6 different sites. I measured damage to plants in two treatments. </p>
<p>There is unequal sampling across years and sites. Species, site and year diffe... | g66170 | [
0.024131763726472855,
-0.06178170442581177,
-0.007954520173370838,
-0.044835165143013,
-0.031324874609708786,
-0.027763890102505684,
0.006228664889931679,
0.038049034774303436,
0.01695721037685871,
0.0161063801497221,
0.04234988987445831,
0.06341534852981567,
-0.0012314226478338242,
-0.024... |
<p>I'm performing a Hausman test in Stata 11. After the test the conclusion is to use FE panel model. In my model I have 6 variables. In FE model only one has a significant effect and in RE model 4 variables have a significant effect on the dependent variable. What do you suggest? To use FE model based on results of Ha... | g36140 | [
-0.009897761046886444,
0.01113407127559185,
0.03193119168281555,
0.008219593204557896,
0.005125108174979687,
0.019962197169661522,
0.04614810273051262,
0.048395439982414246,
0.0014158737612888217,
-0.018114550039172173,
0.0399857796728611,
-0.022561173886060715,
0.042979005724191666,
0.036... |
<p>Say you have a longitudinal data set with 5 measurement points, which begins at 200-300 participants and declines to about 50. There is an intervention between time-point 2 and 3. There's 3 continuous IVs and 1 continuous DV measured at all timepoints. One group. The key interest is the predictive value of the IVs a... | g66171 | [
-0.024227652698755264,
0.0021249959245324135,
-0.01652533933520317,
-0.013625266030430794,
-0.02213725633919239,
-0.018770014867186546,
0.03731698542833328,
0.010939278639853,
-0.01703813672065735,
-0.030016083270311356,
0.021126151084899902,
0.02125636115670204,
-0.0306402500718832,
-0.02... |
<p>How to prove that the radial basis function $k(x, y) = \exp(-\frac{||x-y||^2)}{2\sigma^2})$ is a kernel? As far as I understand, in order to prove this we have to prove either of the following:</p>
<ol>
<li><p>For any set of vectors $x_1, x_2, ..., x_n$ matrix $K(x_1, x_2, ..., x_n)$ = $(k(x_i, x_j))_{n \times n}$ ... | g36145 | [
0.022060813382267952,
-0.003935832064598799,
-0.018829865381121635,
-0.01876259595155716,
0.037764858454465866,
-0.09555414319038391,
0.01944553293287754,
-0.03704249858856201,
-0.014811696484684944,
0.043213795870542526,
-0.04558432474732399,
0.026727398857474327,
0.0038772879634052515,
0... |
<p>I am looking for a free CAS (Computer Algebra System) that is most able to do mathematical statistics. I thought of SAGE, but it doesn't seem to be very powerful.</p>
<p>It can't derive t-distribution : <a href="http://ask.sagemath.org/question/1485/student-t-pdf" rel="nofollow">http://ask.sagemath.org/question/148... | g25077 | [
0.03325783833861351,
-0.004222596529871225,
-0.010969691909849644,
-0.11047754436731339,
-0.06837879866361618,
-0.038460057228803635,
0.03746058791875839,
-0.006660473067313433,
-0.007288304157555103,
-0.0033205649815499783,
0.008235500194132328,
0.010270403698086739,
0.03320091962814331,
... |
<p>I have read possible explanations for Lurking Variables and Influential Observations but I can't seem to construct a good example for myself. </p>
<p><em>A well-designed experiment includes design features that allow researchers to eliminate extraneous variables as an explanation for the observed relationship betwe... | g66172 | [
0.006057561840862036,
0.023677386343479156,
0.0014274505665525794,
-0.04269232973456383,
0.03226780891418457,
0.004101012833416462,
0.05214932560920715,
0.059540361166000366,
-0.013191066682338715,
-0.05548712983727455,
0.0037613660097122192,
0.03662018105387688,
0.05877247452735901,
0.047... |
<p>Is there a good published expository account, with mathematical details, of the various approaches that have been taken to the Behrens–Fisher problem?</p> | g66173 | [
0.016710927709937096,
0.016994714736938477,
0.002627690089866519,
-0.038737181574106216,
0.01682250387966633,
-0.031048625707626343,
0.03053145483136177,
0.025603532791137695,
-0.031448040157556534,
0.04439748078584671,
0.009523608721792698,
0.024509409442543983,
0.05466967821121216,
0.037... |
<p>Let's say I'm analyzing the incidence of pathological lesions, observed during necropsy. No information is available about when the lesion occurred before death. So, I'm using a general linear model $Y_i \sim \beta_0+\beta_{sex}+\beta_{treatment}+\beta_{age}$. $Y_i \in \{0,1\}$ is whether subject $i$ has the lesion ... | g25081 | [
0.017734071239829063,
-0.0625753253698349,
-0.0011274609714746475,
-0.03700157627463341,
-0.0005865719867870212,
-0.024382412433624268,
-0.011446066200733185,
0.008442927151918411,
-0.03616500273346901,
0.03939017280936241,
-0.017944293096661568,
0.013061070814728737,
0.058420535176992416,
... |
<p>I now ran into two variables that give me problems. I know that I want to try to include them in the final model, but I'm unsure how the values should be treated in order to reflect the true nature of the phenomena they are reflecting.</p>
<pre><code>Case 1
</code></pre>
<p>The variable depicts the age/duration of... | g66174 | [
0.023608194664120674,
-0.01309612113982439,
-0.022008003666996956,
-0.057689543813467026,
0.022987110540270805,
0.00012413835793267936,
0.012240596115589142,
0.0015287400456145406,
-0.018924295902252197,
0.0074022505432367325,
-0.031435444951057434,
0.023478925228118896,
0.06543923169374466,... |
<p>This is my topic for the paper I'm working on for an undergrad stats class. It's supposed to be 20 pages... and I'll be honest, I understand very little beyond the basics and am over my head.</p>
<ul>
<li>From what I understand, there several common tests to test if the assumption is violated... Levene's / Bartlett... | g66175 | [
0.04903179779648781,
0.00035455450415611267,
-0.013717020861804485,
-0.056719280779361725,
0.005841569509357214,
-0.05361361429095268,
0.04232354834675789,
0.013365144841372967,
-0.005950638558715582,
0.0009857555851340294,
-0.0008970526396296918,
0.0005329777486622334,
0.04217778518795967,
... |
<p>I'm looking for some facts (theorems or such) concerning the properties of the Student's t-distribution compared to the normal distribution. More specifically, I understand that for the normal distribution the corresponding Student's t-distribution would be lower around the mean and heavier in the tails, and there w... | g66176 | [
-0.012646185234189034,
0.03129059076309204,
-0.009852319024503231,
-0.047405313700437546,
-0.019782498478889465,
-0.013939406722784042,
0.060291942209005356,
0.002061948413029313,
-0.025589242577552795,
0.009877031669020653,
-0.003507888177409768,
-0.011973666027188301,
0.046272486448287964,... |
<p>I have the following hypothesis:</p>
<ul>
<li>Novice drivers perceive road environments as more difficult when there are more pedestrians.</li>
</ul>
<p>I have the following data:</p>
<ul>
<li>The category each driver falls in to (1. Novices, 2. Experienced, 3. Advanced)</li>
<li>Number of pedestrians identified ... | g25084 | [
-0.018886061385273933,
0.010876414366066456,
-0.016191832721233368,
-0.089426189661026,
-0.00037730991607531905,
0.024642881006002426,
0.06404291838407516,
0.02913704328238964,
0.014273252338171005,
0.004516148008406162,
0.04538789018988609,
-0.014459521509706974,
-0.00635853735730052,
0.0... |
<p>I'm reading the book "Collective Intelligence" and in one chapter they introduce how to measure similarity between users on a movie review website with euclidean distance.</p>
<p>Now are the movies rated all on the scale from 1-5. But what if I want to find similar users based on features like - lets say <em>body h... | g66177 | [
-0.021381596103310585,
-0.002047424903139472,
-0.010740682482719421,
-0.008766538463532925,
-0.020344266667962074,
-0.006493524182587862,
-0.007340714335441589,
0.008230878040194511,
-0.07581667602062225,
0.006509782746434212,
0.02612423710525036,
0.026534726843237877,
0.059924595057964325,
... |
<p>I am having difficulty in how to calculate the Pearson's $\chi^2$ statistic for a contingency table with entries: <code>(3, 0)</code> and <code>(0, 3)</code> (row-wise).</p>
<p>I was studying Agresti's categorical data analysis and found this table. He calculated it as 6.</p>
<p>Through what calculation did he rea... | g25087 | [
0.02421751245856285,
0.025900691747665405,
-0.034958794713020325,
-0.025094160810112953,
0.041979752480983734,
-0.04901540279388428,
0.005396753083914518,
0.02448047325015068,
-0.03880755975842476,
0.02040359005331993,
-0.01750977337360382,
0.0598059743642807,
0.015507791191339493,
-0.0269... |
<p>I am currently developing a classificator, which is supposed to classify into a number of classes. For this purpose I am
designing some features and similarity measures which I might use for a later kernel for a SVM.
Now I was thinking to myself, how I can roughly evaluate my features and the similarity measures wit... | g66178 | [
-0.035055194050073624,
-0.040086597204208374,
0.009255471639335155,
-0.012413183227181435,
-0.0273018516600132,
-0.01919269934296608,
-0.005016276612877846,
0.028763681650161743,
-0.05283106118440628,
-0.04430577531456947,
-0.028573311865329742,
0.05139068141579628,
0.027743861079216003,
0... |
<p>I'm currently working on a regression problem where a subset of the predictor variables are zero-sum. By zero-sum I don't mean they all sum to zero, I simply mean that increasing one implies a decrease in one, all or some of the others. This fact makes these variables correlated, but it also means that there is a ... | g66179 | [
-0.01661316491663456,
0.028316406533122063,
0.005013822577893734,
-0.010384690947830677,
0.02199794352054596,
-0.071735680103302,
0.00794771034270525,
0.03918292373418808,
0.0023561001289635897,
-0.0020322168711572886,
-0.012540556490421295,
0.05202684924006462,
-0.00023558788234367967,
0.... |
<p>I have a sequence of densities $f_n(x_n)$, of random variables $X_n$, with means $\mu = 0$ and variances decreasing with $n$:</p>
<p>$$
\sigma^{2}(X_n) = \frac{\sigma^2}{n}.
$$</p>
<p>I am approximating $f_n(X)$ using a normal approximation $N(0, \frac{\sigma^2}{n})$.</p>
<p>I would like to check if the normal ap... | g66180 | [
0.0007529125432483852,
-0.020156703889369965,
-0.012089529074728489,
-0.0130807776004076,
-0.0019023268250748515,
-0.03382646292448044,
-0.009088484570384026,
-0.05937236174941063,
-0.06307713687419891,
-0.020975055173039436,
0.005601406563073397,
0.04031097888946533,
0.030689820647239685,
... |
<p>I would like to evaluate several different models that provide
predictions of behavior at a monthly level. The data is balanced, and
$n=$100,000 and $T=$12. The outcome is attending a concert in a given
month, so it is zero for ~80% of the people in any month, but there's
a long right tail of heavy users. The predic... | g25090 | [
-0.020470425486564636,
-0.019782036542892456,
0.004419037140905857,
0.013403784483671188,
-0.008178713731467724,
-0.024005139246582985,
0.11143378913402557,
0.01975005865097046,
0.028714023530483246,
-0.04764392971992493,
0.02036311663687229,
-0.010953279212117195,
0.04369774088263512,
0.0... |
<p>OK, I get that PCA can be used for dimensionality reduction but there's something basic escaping me.</p>
<p>Let's say I have a feature set $F$ of $N$ features. After I run PCA which of the following are true about the resulting feature set.
1) It will be a subset of the original feature set $F$ with $< N$ featur... | g66181 | [
-0.007183218374848366,
-0.024613656103610992,
0.030016275122761726,
-0.011123167350888252,
-0.03455434739589691,
-0.035483941435813904,
0.08697255700826645,
0.055709999054670334,
-0.07201911509037018,
-0.07270307838916779,
-0.005527902860194445,
0.04496435075998306,
0.025891806930303574,
0... |
<p>Say I have a 24x7 matrix in which the rows represent hours in the day and the columns represent the days of the week. The values in this matrix represent the number of people present at a particular place.
Mathematically speaking the values are thus the result of a function: presence(hour, day)</p>
<p>I am looking ... | g66182 | [
0.015085771679878235,
-0.03174133971333504,
0.0029814252629876137,
-0.06281904131174088,
0.04851192981004715,
-0.014973090030252934,
0.023689180612564087,
-0.030850181356072426,
-0.057744819670915604,
-0.011566323228180408,
-0.013385984115302563,
-0.032989826053380966,
0.037763964384794235,
... |
<p>I am computing the interaction in several 2X2X2 tables (i.e. in each case, I have eight frequencies), see for an example <a href="http://gjyp.nl/files/2x2x2.xls" rel="nofollow">this file</a>.</p>
<p>I have two predictors (low vs high 'threat' and low vs high 'efficacy') and one dependent variable (whether people pe... | g25092 | [
0.004823905415832996,
0.012448376044631004,
-0.004851373378187418,
-0.03912463039159775,
0.003742259694263339,
-0.04983319342136383,
0.015398199670016766,
0.0032315871212631464,
-0.05445342883467674,
-0.05482565239071846,
0.011882037855684757,
0.044361893087625504,
0.04189251735806465,
-0.... |
<p>For a simple 2 variables (say X and Y) cointegration test, how does it affect our analysis, if we perform regression on X and Y with and without the intercept, and then test the spread for stationarity.</p>
<p>I am doing this analysis for stocks.</p> | g66183 | [
0.058327335864305496,
-0.024406656622886658,
-0.007472134195268154,
-0.006761997006833553,
0.0010829265229403973,
-0.05333784967660904,
0.04737938940525055,
0.05499846488237381,
-0.019588492810726166,
-0.03535228967666626,
-0.02259729616343975,
0.03125287964940071,
-0.00935481395572424,
0.... |
<p>Could anyone please elucidate the difference between <code>Vector Autoregressive Models with exogenous variables, VARX(p,q</code>) and <code>autoregressive distributed lag models ADL(p,q)</code>? Based on the descriptions of two models, they appear to be the same so why different names are given?</p> | g25096 | [
0.0497305765748024,
-0.04699568450450897,
-0.01970282383263111,
-0.010123700834810734,
0.058495596051216125,
0.012414193712174892,
0.015614718198776245,
-0.035075247287750244,
-0.029037991538643837,
0.032677583396434784,
-0.04655098170042038,
0.024782782420516014,
0.04454082250595093,
0.02... |
<p>I feel a bit uneasy with how I've mentally dealt with Borel's paradox and other associated "paradoxes" dealing with conditional probability. For those who are reading this that aren't familiar with it, see <a href="http://en.wikipedia.org/wiki/Borel%E2%80%93Kolmogorov_paradox">this link</a>. My mental response up to... | g13 | [
0.03208620846271515,
0.001144173089414835,
0.006521985866129398,
0.011305231600999832,
-0.0075469957664608955,
-0.04306516796350479,
0.04241586849093437,
0.017492515966296196,
-0.008619209751486778,
-0.05705602839589119,
-0.007186010014265776,
0.0492616631090641,
-0.002438911469653249,
0.0... |
<p>What are the most used/popular artificial neural network algorithms for recognising the content of images in general?</p>
<p>E.g.</p>
<ul>
<li>If the picture is of a person, dog, cat or a car.</li>
<li>If the picture is a landscape, indoor or some banner or advert.</li>
</ul>
<p>etc.</p>
<p>I've heard of backpro... | g17169 | [
0.06768185645341873,
-0.030003640800714493,
-0.0002912418858613819,
-0.04787345975637436,
0.003609399776905775,
-0.07812611758708954,
0.02044363133609295,
0.02978999726474285,
0.00020148079784121364,
0.032739799469709396,
0.0183841772377491,
-0.006530955899506807,
0.09515319764614105,
0.02... |
<p>I need to fit a regression model using least squares in R with the constraint that the parameters are positive. they DON'T need to sum to one. because some times parameter sum exceeds one.</p>
<p>Can someone help me with the code pease</p> | g66184 | [
0.025886056944727898,
0.008479312993586063,
0.0019421435426920652,
-0.030961154028773308,
-0.03515474870800972,
-0.008514013141393661,
0.004337412770837545,
0.02609994448721409,
-0.037860214710235596,
0.015918022021651268,
-0.030297083780169487,
-0.0023239252623170614,
-0.0034830919466912746... |
<p>Background/how this came up: </p>
<p>A student has numeric ratings on a variety of items in questionnaires and sports performance data and would like to model the performance on questionnaire scores. He wanted to do an analysis (don't ask me why) where some of the data are split into quantiles so he can compare hig... | g45317 | [
-0.04208005964756012,
0.004538705572485924,
-0.025228481739759445,
-0.03801034018397331,
-0.008323023095726967,
-0.020225560292601585,
-0.0012187666725367308,
-0.024367524310946465,
-0.03498891368508339,
-0.01815861091017723,
0.06269734352827072,
-0.007669437676668167,
-0.01368205901235342,
... |
<p>I'm doing a small reinforcement learning project involving Tetris, just for fun.</p>
<p>Considering that each piece has a constant probability of being selected, how can I calculate the probability of receiving a <em>specified next piece</em>, given the record of the previous spawned pieces? (maybe the piece sequen... | g66185 | [
-0.027025369927287102,
0.025148600339889526,
-0.014552410691976547,
-0.06679234653711319,
-0.06157299876213074,
-0.0403662845492363,
0.03713248297572136,
0.02529166452586651,
-0.04406503960490227,
0.005253519397228956,
-0.050932690501213074,
0.03707345947623253,
0.029720548540353775,
0.012... |
<p>I am constructing Markov chains (with 100 to 200 states) and inferring transition probabilities empirically by simply counting how many times I saw each transition in my raw data (about 20k to 60k transitions per data set). Note that the modest number of transitions and the decent number of state results in average ... | g676 | [
0.011044373735785484,
-0.03958349674940109,
0.014869673177599907,
0.01137507800012827,
-0.03546499088406563,
-0.07640419155359268,
0.01801038347184658,
0.03948763385415077,
-0.013775289058685303,
-0.0005708839162252843,
-0.00923141185194254,
0.030731376260519028,
0.05219356715679169,
-0.00... |
<p>I have a data set with about 70 variables that I'd like to cut down. What I'm looking to do is use CV to find most useful variables in the following fashion. </p>
<p>1) Randomly select say 20 variables. </p>
<p>2) Use <code>stepwise</code>/<code>LASSO</code>/<code>lars</code>/etc to choose most important variab... | g66186 | [
0.024484317749738693,
-0.059876274317502975,
0.0005521446000784636,
-0.054772574454545975,
-0.016584055498242378,
-0.08569309115409851,
0.039452046155929565,
0.004300812724977732,
-0.012493747286498547,
-0.0021720065269619226,
0.042339302599430084,
0.03165021538734436,
0.037416547536849976,
... |
<p><strong>Edited Question:</strong></p>
<p><em>As I promised I've edited this question. The previous version was written with the intention of simplifying the real question, but it ended in losing the real significance. Now I'm posting the "whole story". ;)</em></p>
<p>My purpose is to calculate $n$ players' equity... | g25108 | [
0.014245984144508839,
0.010333430022001266,
-0.00023624757886864245,
-0.016262879595160484,
-0.030166588723659515,
-0.056193262338638306,
0.0018925401382148266,
0.02512558549642563,
-0.014154134318232536,
0.04961083084344864,
-0.0053766025230288506,
0.055299390107393265,
-0.02802555635571479... |
<p>I'm trying to understand the emphasized phrase in the following passage:</p>
<blockquote>
<p>The usual method of determining the probability that the mean of the population lies within a given distance of the mean of the sample is to assume a normal distribution about the mean of the sample with <em>a standard de... | g49743 | [
0.015964791178703308,
0.03675989434123039,
0.007320410571992397,
-0.004229039419442415,
-0.03646090254187584,
0.0017716214060783386,
0.04524083435535431,
0.002860392676666379,
-0.02880626730620861,
-0.004524993244558573,
-0.004977354314178228,
0.014949848875403404,
-0.0004291110089980066,
... |
<p>R and stat noob here. I have been playing with Jeromy Anglim's code in his blog post <a href="http://jeromyanglim.blogspot.com/2010/11/sweave-tutorial-3-console-input-and.html" rel="nofollow">here</a>. However, my <code>items$variable</code> has some missing values. I tried using the <code>distractor.analysis</code>... | g25111 | [
0.01425680797547102,
-0.07717087119817734,
0.00730243232101202,
-0.012940687127411366,
-0.02068994753062725,
0.021875785663723946,
0.08907753974199295,
-0.040548160672187805,
-0.029750719666481018,
-0.0009818397229537368,
0.01790504716336727,
-0.009465260431170464,
0.01980794407427311,
0.0... |
<p>I am running some data analysis on a site that lets users share a ride. What I am trying to determine is what separates users who are successful in offering rides and users who are less successful. This is in order to provide some tips to less successful users.</p>
<p>The research question I'm trying to answer now ... | g66187 | [
-0.04260438308119774,
0.013874868862330914,
-0.03032829239964485,
-0.00045467179734259844,
0.012693596072494984,
-0.02096136100590229,
0.031323548406362534,
-0.023796798661351204,
-0.038358837366104126,
0.00033495103707537055,
0.04389689117670059,
-0.037611912935972214,
0.036343637853860855,... |
<p>I'm trying to figure out exactly what the difference is between $t$-tests and $z$-tests.</p>
<p>As far as I can tell, for both classes of tests one uses the same test statistic, something of the form</p>
<p>$$\frac{\hat{b} - C}{\widehat{\operatorname{se}}(\hat{b})}$$</p>
<p>where $\hat{b}$ is some sample statisti... | g66188 | [
0.017234742641448975,
-0.014403828419744968,
-0.0060495357029139996,
0.016604362055659294,
0.009093277156352997,
-0.02539123222231865,
0.10719364881515503,
0.03093358688056469,
0.0022804320324212313,
0.021594371646642685,
-0.01705332100391388,
0.017032818868756294,
0.01226914580911398,
-0.... |
<p>I was hoping that I could get some feedback in terms of keywords I should searching for, or concepts I need to consider with the following:</p>
<p>I have non-experimental data that I would like to model in a regression format. Unfortunately, I only have 12 subjects and a set of repeated measures of 6 observations:... | g66189 | [
-0.019923176616430283,
0.0008925085421651602,
-0.032436154782772064,
-0.032164644449949265,
-0.01824411004781723,
-0.005175809841603041,
0.03547808527946472,
-0.02593649923801422,
0.008224111050367355,
-0.032949578016996384,
0.022011520341038704,
-0.012203873135149479,
0.038296010345220566,
... |
<p>Let's analyse the following binary choice model:
$$Y^*_i = X_i^T \beta + \varepsilon_i\\
\varepsilon_i \sim F \\
Y_i = \mathbb{I} \{X_i^T \beta + \epsilon_i > 0\}$$
where $F$ is determined by a finite number of parameters $\gamma$. Define $\theta = (\beta^T, \gamma^T)^T$.</p>
<p>$$L(\theta) = \sum_{i = 1}^{N} Y_... | g66190 | [
-0.023332685232162476,
0.024929795414209366,
0.006198039744049311,
0.057630591094493866,
0.0607244037091732,
-0.041302621364593506,
0.05024757981300354,
-0.013163244351744652,
-0.040631186217069626,
0.009002475067973137,
-0.08270642906427383,
0.07139763981103897,
-0.014078757725656033,
0.0... |
<p>We are trying to do a POC on using <code>NaiveBayes</code> to classify an establishment by the category.</p>
<p>We loaded the following training set in R. </p>
<pre><code>NAME_1,NAME_2,CHANNEL_5
Vanilla,Bar,Bar & Grill
Zen,Bar,Bar & Grill
cafe,havana,Bar & Grill
cafe,hollywood,Bar & Grill
mona... | g25116 | [
-0.03658962994813919,
-0.012932931073009968,
0.004540687892585993,
-0.060355279594659805,
0.05096074938774109,
-0.028721416369080544,
0.04913070425391197,
0.03236199542880058,
-0.05615822970867157,
-0.019304385408759117,
0.04646892845630646,
0.026221437379717827,
0.019351467490196228,
-0.0... |
<p>I have a dataset with two classes and the ratio of the number of instances in two classes is 1:10. I used SVM for classification and obtained a pathetic performance as it classified all the instances in the larger class. Is there a classifier which is shown to perform well in case of biased datasets? </p> | g66191 | [
0.03299381211400032,
0.025629226118326187,
0.008411457762122154,
-0.0801083967089653,
-0.022277161478996277,
-0.06575770676136017,
0.011515975929796696,
0.03424658253788948,
-0.006874872837215662,
-0.00022838912263978273,
0.05991997569799423,
0.01193513348698616,
0.06971918046474457,
0.065... |
<p>I am currently working on a project dealing with time series data but I have little experience with time series analysis so I was hoping to get some direction on what kind of exploratory data analysis techniques and models I should be looking at, so that I can read up on my own.</p>
<p>I have two weekly time series... | g66192 | [
0.010781845077872276,
0.03781869262456894,
-0.005939728580415249,
-0.02674512378871441,
-0.0036123383324593306,
0.0037222616374492645,
0.05073460564017296,
0.026031402871012688,
-0.020734019577503204,
-0.025169895961880684,
0.034005701541900635,
-0.03292011842131615,
0.027413539588451385,
... |
<p>If you have the following correlations for the following variables:</p>
<pre><code>Ugrad GPA and Grad GPA .579
GRE and Grad. GPS .650
GRE and Ugrad GPA .767
Interview and Grad GPA .321
Interview and Ugrad GPA .221
Interview and GRE .333
Gender and Grad GPA .278
Gender adnd Ugrad GPA .101
G... | g25119 | [
0.01814393885433674,
-0.031015731394290924,
0.007818548008799553,
0.007424961309880018,
-0.01934581808745861,
0.020831340923905373,
0.03379930928349495,
0.05459858104586601,
-0.02469421550631523,
-0.002480542054399848,
0.03218581900000572,
0.004059532657265663,
0.03058931976556778,
0.00941... |
<p>I am looking into time series data compression at the moment.</p>
<p>The idea is to fit a curve on a time series of n points so that the maximum deviation of any of the points is not greater than a given threshold. In other words, none of the values that the curve takes at the points where the time series is define... | g47916 | [
0.015456249937415123,
-0.03302286937832832,
0.01023760624229908,
-0.0328022800385952,
-0.042857371270656586,
-0.07080588489770889,
-0.06028980389237404,
0.0515725314617157,
-0.04498793184757233,
0.02570103108882904,
-0.02341637760400772,
-0.02165447734296322,
0.03813009709119797,
0.0287299... |
<p>I am fairly new to statistics.
Currently I am into (histograms) medians, arithmetic mean and all the general basics.
And I came across the fact/rule that the arithmetic mean is (always) larger than the median if the distribution is skewed to the right.</p>
<p>Why is that?<br>
(I would appreciate a rather simple or ... | g25122 | [
-0.004553993232548237,
0.04320518672466278,
-0.019417988136410713,
-0.017053816467523575,
-0.007035946939140558,
0.015216853469610214,
-0.027092887088656425,
0.0588136650621891,
-0.038661643862724304,
-0.019677964970469475,
0.004353385418653488,
0.015225732699036598,
0.029166992753744125,
... |
<p>If the minimum is not unique and the MLE is equal to zero over a range of functions, how can we find the minimum? I have read about golden section search algorithm or bisection algorithm, but I don't know if they would apply in this case or not? Is there any other better algorithm which is faster than these algorith... | g45325 | [
0.037017133086919785,
-0.012225011363625526,
0.007971256971359253,
0.02352692186832428,
-0.04308204725384712,
-0.07667217403650284,
0.0064756786450743675,
0.014275707304477692,
-0.04579239711165428,
-0.00231378385797143,
-0.01201882865279913,
0.047155581414699554,
0.036122336983680725,
0.0... |
<p>I have 3 random variables, A, B and C. Given A, variables B and C are independent. I have estimates of the variance of A, B and C and the covariance between A and B and A and C. Is it possible calculate an implied covariance between B and C?</p>
<p>My application is that I have a large number of random variables (... | g66193 | [
-0.031845904886722565,
-0.0006205035024322569,
0.01037515327334404,
-0.07310780882835388,
-0.0324883759021759,
0.006126835942268372,
-0.024114757776260376,
0.03291543573141098,
-0.06265635043382645,
0.033515576273202896,
-0.017673974856734276,
0.020977646112442017,
-0.050180379301309586,
0... |
<p>So I have this data set of 56 users with 52 weeks worth of weekly average data for blood pressure and exercise level recordings. I would like to use change point analysis (https://sites.google.com/site/changepointanalysis/) in R to understand where changes are occurring. However to make CPA usable, the observations ... | g25124 | [
0.06635011732578278,
-0.0667581632733345,
-0.010571136139333248,
-0.028494492173194885,
0.009604296647012234,
-0.06420888006687164,
0.09603600949048996,
0.0003318225499242544,
-0.03982210159301758,
0.007219650782644749,
0.037400390952825546,
0.08415607362985611,
0.03408730775117874,
-0.007... |
<p>I am trying to build a model to predict one year ahead Earnings per share $(t+1)$ based on variables in year $t$.
I’ve seen a lot of models in practice that use the following methodology:</p>
<pre><code>Earnings(t+1)/#_of_shares(t) ~ x1(t) +x2(t)+x3(t)
</code></pre>
<p>and I’m wondering whether</p>
<pre><code> E... | g31068 | [
0.0009340637479908764,
-0.032250333577394485,
0.015365623869001865,
0.004302422981709242,
-0.05303891375660896,
-0.02592325396835804,
0.0514015294611454,
0.025501376017928123,
-0.03644103929400444,
-0.02459590695798397,
0.06295458972454071,
0.005586974322795868,
0.04101692885160446,
-0.001... |
<p>I'm investigating the asymptotic normality of the estimators of the logistic model. I wish to do a simulation to show that the standard error decreases as sample size n increases. Assume i have explanatory variables x1, x2,...,x7 and response variable y. How do I do this?</p> | g25127 | [
-0.0015367096057161689,
0.04253153130412102,
0.012670877389609814,
-0.03872581943869591,
0.03770069777965546,
-0.06117332726716995,
-0.02376219443976879,
-0.01859099045395851,
-0.03093872033059597,
-0.0036189407110214233,
-0.006111899856477976,
0.026087922975420952,
0.028628190979361534,
0... |
<p>In my experiment I compare the jump height of participants pre and post 2 separate interventions.</p>
<p>All participants completed baseline measures of jump height. Participants then underwent a training intervention followed by post test measurements. On a separate occasion the same participants completed a diffe... | g37441 | [
0.006398932076990604,
-0.027241453528404236,
0.011918798089027405,
-0.03568852320313454,
-0.03355704993009567,
-0.0022951732389628887,
0.04906176030635834,
0.01889561302959919,
-0.036605264991521835,
-0.023579882457852364,
-0.0012729106238111854,
0.0012458722339943051,
-0.03252265974879265,
... |
<p><strong>Which statistical test should I use</strong> to answer the following 3 questions, using the data collected as follows:</p>
<p>12 sailors participated in a day long regatta, in which there were 3 races. In every race, all sailors participated and times were recorded. The course was the same for each race and... | g47991 | [
0.021498097106814384,
-0.004642778541892767,
0.017751000821590424,
-0.026897648349404335,
-0.040764156728982925,
0.024764668196439743,
0.03195539861917496,
0.0011116029927507043,
0.03566708415746689,
-0.045852549374103546,
0.017469137907028198,
0.03493252396583557,
0.05404982343316078,
-0.... |
<p>I am currently doing some tests with some specific parameter settings to characterize a process.</p>
<p>I roughly remember that a widely used rule of thumb for lab tests and whatnot is a sample size of 5 or 6. Even my tutor said to do the same test 5 times. It's what were told in two of our undergraduate courses. <... | g66194 | [
0.055566586554050446,
0.00882105901837349,
0.00531351612880826,
-0.036836519837379456,
-0.041750192642211914,
-0.049321211874485016,
0.013870323076844215,
0.008139926940202713,
-0.020898975431919098,
-0.011875603348016739,
0.041459061205387115,
-0.023455290123820305,
0.0231409203261137,
0.... |
<p>I have calculated a posterior distribution where the highest probability (peak of posterior-curve) is at 99%. But the mean probability is lower, at about 98%. This is of course because "the curve" stretches much further toward 0 than it can toward 100.</p>
<p>I see in literature that the mean value is what matters ... | g66195 | [
0.04431585222482681,
0.014875365421175957,
-0.007242524065077305,
0.0037920766044408083,
0.02902333065867424,
-0.029382452368736267,
-0.0007289679488167167,
0.023561054840683937,
0.0005898380768485367,
-0.027448564767837524,
0.010145200416445732,
0.02775377407670021,
0.07714062929153442,
-... |
<p>On page 26 in the <a href="http://cran.r-project.org/web/packages/rugarch/vignettes/Introduction_to_the_rugarch_package.pdf" rel="nofollow">rugarch package</a> you can see plots of autocorrelations. I want to use this autocorrelation plots, but not for my final model checking, but for my model identification. So the... | g66196 | [
0.05953579768538475,
-0.09151211380958557,
0.01434844359755516,
-0.04875383526086807,
-0.03064032644033432,
-0.0187003705650568,
0.05216405168175697,
-0.03217928111553192,
-0.04134329780936241,
-0.044469352811574936,
0.016678690910339355,
0.0031743452418595552,
0.00798032432794571,
-0.0235... |
<p>I'm searching for books on the basic k-means and divisive clustering algorithms. I'm interested in the pros and cons of both. It's a part of my bachelors thesis, I have implemented both and need books to create my used literature list for the theoretical part.
Also, is there a book on "the curse of dimensionality"? ... | g49744 | [
0.01800927333533764,
-0.003080191556364298,
0.023319926112890244,
0.003885935992002487,
-0.014464099891483784,
-0.009863540530204773,
-0.05123153328895569,
0.007783812936395407,
-0.04221324250102043,
0.004411442670971155,
0.057467009872198105,
-0.009381609968841076,
0.11732679605484009,
0.... |
<p>When you collect data from participants in an experiment, sometimes you can collect repeated responses for <em>the same condition</em>, e.g., in R:</p>
<pre><code>set.seed(2012) # keep the example the same each time.
data.full <- data.frame(id=gl(10, 4),
condition=gl(2, 40),
... | g66197 | [
-0.0006512743420898914,
-0.055601567029953,
0.015791740268468857,
-0.08347895741462708,
-0.0030351385939866304,
0.04829888418316841,
0.009172388352453709,
0.0009534875280223787,
-0.03329094499349594,
-0.03241098299622536,
0.022227158769965172,
-0.003893323941156268,
0.030591610819101334,
0... |
<p>Let $D$ be a positive random variable with $\mathrm{E}[D] < \infty$. Assume that there exist $y>0$ and $\epsilon>0$ such that: $P(D > \mathrm{E}[D]+y) > \epsilon$. Prove that there exist other $y'>0$, $\epsilon'>0$ such that: $P(D < \mathrm{E}[D]-y') > \epsilon'$.</p>
<p>In words, if ther... | g66198 | [
0.010995656251907349,
0.030581997707486153,
-0.006027678027749062,
-0.05490413308143616,
-0.0058771236799657345,
-0.006236308719962835,
0.01496518962085247,
0.015029983595013618,
-0.015176924876868725,
-0.04911651089787483,
-0.010718921199440956,
0.030200783163309097,
-0.050536490976810455,
... |
<p>I need advice on what is a a reasonable number of cases to be deleted as outliers. </p>
<p>I have conducted an outliers analysis to identify univariate and multivariate outliers from my dataset. Alltogether 30% of the data was classified as outliers.</p>
<p>If I delete all of these outliers, my results appear to i... | g43077 | [
0.035167258232831955,
-0.011116107925772667,
0.04216235876083374,
-0.0005991557845845819,
-0.021396195515990257,
-0.012032764963805676,
0.012263478711247444,
0.0028801190201193094,
-0.005794664844870567,
0.021333223208785057,
0.022449729964137077,
0.028065001592040062,
-0.016386637464165688,... |
<p>Let's say that I have twenty candidates in a political race and that I want to run tests on the success of each candidate based on a variety of <a href="http://en.wikipedia.org/wiki/Voting_system#Multiple-winner_methods" rel="nofollow">voting systems</a>. Is there a software that allowed me to do this, i.e. enter th... | g66199 | [
-0.06439945846796036,
0.02082415483891964,
-0.021069075912237167,
-0.012259363196790218,
-0.010577480308711529,
-0.02667960524559021,
-0.01925695315003395,
0.009624196216464043,
-0.025196896865963936,
-0.01847999170422554,
-0.007540175691246986,
-0.02281944267451763,
0.023411359637975693,
... |
<p>I am struggling at the moment with how to determine links between different sets of variables. I have data on land use/cover changes in a number of regions in a period of 20 years. They are all expressed in percentages of area surface changed. I have data on so called drivers of change (population change, employment... | g66200 | [
0.023382365703582764,
-0.06509310007095337,
-0.011254114098846912,
-0.03187980875372887,
-0.01517004519701004,
-0.014784270897507668,
-0.006935874465852976,
-0.004233349114656448,
0.0006903497851453722,
-0.030395839363336563,
0.04473194479942322,
0.0035172966308891773,
0.02455052174627781,
... |
<p><br>
I'm trying to understand the logic behind the ANOVA F-test in Simple Linear Regression Analysis. The question I have is like follows. When the F value, i.e.
<code>MSR/MSE</code> is large we accept the model as significant. What is the logic behind this?</p> | g4959 | [
0.028567837551236153,
0.03236351162195206,
-0.008033431135118008,
0.04401617497205734,
-0.0029322889167815447,
0.02119954116642475,
0.02478519082069397,
0.07693101465702057,
-0.040845710784196854,
-0.019452618435025215,
-0.039815470576286316,
-0.03070686198771,
0.07234258949756622,
0.04675... |
<p>I am studying Gary Koop's <em>Bayesian Econometrics</em> , it is bit confusing in the beginning. I will reproduce some results from the textbook here in order to smoothly move to my question. </p>
<p>For a simple linear regression model with normal distribution assumption for the error term, its <strong>likelihood<... | g25132 | [
0.006216048263013363,
-0.04013005271553993,
-0.007394941058009863,
-0.016457706689834595,
0.023741647601127625,
0.010880899615585804,
0.057586055248975754,
0.005906697828322649,
-0.03488490357995033,
0.000743131444323808,
-0.042488932609558105,
0.07423391193151474,
-0.03685036674141884,
-0... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.