question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Some colleagues asked me to perform a residual analysis on both linear models and generalized estimating equation (GEE) models. I know it is a faux-pas in some circles to remove outliers, but in our field it is common as a sensitivity analysis. In R, there are some great tools as diagnostics for linear models in the... | g68635 | [
0.011830792762339115,
-0.12671710550785065,
0.0023699519224464893,
-0.05323212593793869,
-0.03554283082485199,
0.004030467476695776,
0.04797907918691635,
0.007339362520724535,
-0.04475370794534683,
0.04194876179099083,
-0.016456587240099907,
0.051503054797649384,
-0.008296558633446693,
0.0... |
<p>I created a $k$-means with 3 clusters. Some of the variables had a big scale, so I used a $z$-score to standardize them. The others (mostly dummies), I left as is.</p>
<p>Now, when I create the table of all variable centers for each cluster, obviously the ones I standardized are still expressed in the $z$-score for... | g68636 | [
-0.019327769055962563,
-0.029538903385400772,
-0.025226974859833717,
-0.057213082909584045,
0.02368457242846489,
-0.05727248638868332,
-0.0012586046941578388,
0.040835220366716385,
0.013847365975379944,
0.010211640037596226,
-0.028779540210962296,
0.024858253076672554,
0.08584568649530411,
... |
<p>I'm interested in exploring statistical models (or modifications thereof) designed to handle a specific type of problem. Due to my ignorance of statistical terminology, I can only describe this type of problem by (contrived) examples:</p>
<p>Suppose we're interested in estimating the likelihood that a given cell ph... | g68637 | [
-0.033029038459062576,
-0.042649418115615845,
0.0003780050028581172,
-0.005328738130629063,
-0.015990277752280235,
-0.022165782749652863,
0.029680587351322174,
0.05866003409028053,
0.014028530567884445,
0.02992144413292408,
-0.014935692772269249,
0.01474048662930727,
0.06583906710147858,
0... |
<p>I will describe the design of the experiment briefly.</p>
<ol>
<li><p>The task have two within-subject variables ($A$ and $B$), </p>
<p>A. have two levels</p>
<p>B. have three levels</p></li>
<li><p>one repeated variable with 5 levels ('time lag' 1,2,3,4,5).</p></li>
<li><p>Subjects are two groups.</p></li>
</ol>... | g68638 | [
-0.005746348295360804,
-0.07627703249454498,
-0.011785740032792091,
-0.07895230501890182,
0.02051725797355175,
-0.024298423901200294,
0.03569888696074486,
-0.02207588404417038,
-0.0467715710401535,
-0.022855350747704506,
-0.014094694517552853,
0.06821377575397491,
-0.019698292016983032,
0.... |
<p>I have one general question. Suppose you are given two regression lines of the variables x and y: Say-
4x-6y+50=0 and 15x-6y-120=0. Then how to identify among these two regression equations, the one which is Y on X and the one which is X on Y?</p> | g49431 | [
0.021931393072009087,
-0.06850182265043259,
-0.018892161548137665,
0.004369213245809078,
0.027340993285179138,
-0.07463840395212173,
0.027635930106043816,
-0.024723097681999207,
-0.0011343855876475573,
-0.04008040204644203,
-0.008226471953094006,
0.06877463310956955,
0.02941751293838024,
-... |
<p>I am working on a project and have to find a way to break my data into percentiles.
<strong>The variables that I already have are gender, age in months and BMI. If I am able to calculate the percentile that each child falls into, I will then be able to label them as underweight, normal weight, overweight and obese.<... | g68639 | [
0.00392493512481451,
-0.021459616720676422,
-0.017101110890507698,
-0.06744213402271271,
-0.03598334640264511,
-0.004694723524153233,
0.04193497821688652,
-0.02666313387453556,
-0.03147342428565025,
-0.04156123474240303,
0.026322675868868828,
-0.012692036107182503,
0.03210337460041046,
-0.... |
<p>What is the meaning of $\|a\|_p=\left(\sum _{i=1}^n \left|a_i(t)\right|{}^p\right){}^{\frac{1}{p}}$?</p>
<p>This formula is called out on the fifth page of <em>An Improved Data Stream Summary: The Count-Min Sketch and its Applications</em> (which can be found <a href="http://www.madalgo.au.dk/img/SumSchoo2007_Lectu... | g38683 | [
0.0014200367731973529,
0.03153928741812706,
-0.05116041377186775,
-0.04873845726251602,
-0.017881276085972786,
-0.006700069177895784,
0.07853388786315918,
-0.04266677796840668,
-0.03270149603486061,
-0.047128550708293915,
-0.07898576557636261,
0.04575762152671814,
0.019604548811912537,
0.0... |
<p>Can we instead of doing logistic or multinomial regression do two or multiple Poisson regressions and then combine Poisson predictions to get probabilistic predictions? If yes, how should we transform data for training? </p> | g68640 | [
-0.011104712262749672,
-0.0012642383808270097,
0.017311187461018562,
-0.02217007800936699,
0.010073734447360039,
-0.06633640825748444,
-0.05473020300269127,
0.03191728517413139,
-0.027287477627396584,
-0.04947475716471672,
-0.020462529733777046,
-0.023382913321256638,
0.015507274307310581,
... |
<p>I am wondering how one should <em>properly</em> analyse longitudinal data from simple experiments (not observational studies). Imagine an experiment where subjects are first measured at baseline, randomised to different treatments and then followed for a number of time periods. We are interested in differences (typi... | g68641 | [
0.04797995090484619,
-0.05689424276351929,
-0.0013087765546515584,
-0.027189135551452637,
0.023213544860482216,
0.023848872631788254,
0.057500485330820084,
-0.004729298874735832,
-0.05604581907391548,
0.015705451369285583,
0.033967360854148865,
0.0041954778134822845,
-0.005006159655749798,
... |
<p>Hierarchical clustering can be represented by a dendrogram. Cutting a dendrogram at a certain level gives a set of clusters. Cutting at another level gives another set of clusters. How would you pick where to cut the dendrogram? Is there something we could consider an optimal point? If I look at a dendrogram across ... | g38687 | [
0.0321415513753891,
0.03067898564040661,
0.0063679032027721405,
-0.0248907208442688,
0.014857670292258263,
-0.04581892117857933,
0.01332180853933096,
0.015212765894830227,
-0.06900785118341446,
0.026529934257268906,
0.017272697761654854,
0.008725445717573166,
0.04282379895448685,
0.0050826... |
<p>I have a simple document classification problem where i need to classify some documents to a definite set of classes.</p>
<p>I need to perform a feature selection (where I will select the most important words from each class).</p>
<p>Currently I am calculating the tf-idf scores. Is there a better way to do that ?... | g38688 | [
-0.013105175457894802,
0.00031955839949660003,
0.020225463435053825,
-0.06790953129529953,
0.014844322577118874,
-0.08349697291851044,
0.015575365163385868,
0.026629073545336723,
-0.04672980681061745,
0.02617228776216507,
0.01121123880147934,
-0.003980411682277918,
0.08057549595832825,
0.0... |
<p>I am <em>very</em> new to functional data analysis (FDA). I am reading: </p>
<blockquote>
<p>Ramsay, James O., and Silverman, Bernard W. (2006), Functional Data
Analysis, 2nd ed., Springer, New York.</p>
</blockquote>
<p>However, I am still not very clear where/when to use FDA? Could someone please give me an ... | g68642 | [
0.029275115579366684,
0.01941746473312378,
0.016685588285326958,
0.006711730733513832,
-0.0268856268376112,
-0.029043084010481834,
0.052689313888549805,
0.04101983457803726,
-0.026089318096637726,
-0.02323015406727791,
0.009782963432371616,
0.07555199414491653,
0.08015424013137817,
0.01351... |
<p>I have a streaming data set, examples are available one at a time. I would need to do multi class classification on them. As soon as I fed a training example to the learning process, I have to discard the example. Concurrently, I'm also using the latest model to perform prediction on unlabelled data.</p>
<p>As far ... | g49629 | [
0.023132864385843277,
0.037506476044654846,
0.018559500575065613,
0.013853458687663078,
-0.024249618873000145,
-0.07534150034189224,
0.010877964086830616,
0.06178029626607895,
-0.04418633133172989,
0.01065538264811039,
0.0013849252136424184,
0.031320925801992416,
0.03702991455793381,
0.082... |
<p>I have a pre-test, post-test, non-equivalent groups experiment, with a sample of 62 (control and experimental groups have 31 each). My objective is to compare the effectiveness of a model of teaching for developing vocabulary among pupils with different learning styles. The learning styles of the 31 of the experime... | g68643 | [
-0.048401858657598495,
-0.02504902519285679,
-0.008411712013185024,
-0.07157334685325623,
-0.0014056877698749304,
-0.01585458777844906,
-0.023276424035429955,
0.02408234030008316,
0.014741427265107632,
-0.006587405689060688,
0.0673372894525528,
-0.01669212244451046,
0.006930691655725241,
0... |
<p>I am trying to plot an exponential curve (<code>nls</code>) through this data set in R.</p>
<p>abm is a text file with the following data=</p>
<pre><code>x=
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,2,2,1,2,1,2,2,2,2,2,1,2,2,1,3,1,3,1,2,1,2,2,3,3,2,3,3,3,2,3,3,2,1,5,5,1,4,3,4,3,3,5,7... | g28738 | [
0.01813153736293316,
-0.03771005943417549,
0.013296741992235184,
-0.08752324432134628,
0.026301058009266853,
-0.01756509765982628,
0.027661848813295364,
-0.0640648826956749,
-0.0694470927119255,
0.0021529910154640675,
0.02282082289457321,
0.05422677472233772,
0.037806518375873566,
-0.03169... |
<pre><code>for (i in 1:160) {
situps[i] ~ dnorm(mu[i],prec[gender[i]+1]);
mu[i] <- b0+b1[gender[i]]+b2[health[i]]+b1b2[health[i],gender[i]];
}
b0 ~ dnorm(0,.001);
for (i in 1:4) {
b2[i] ~ dnorm(0,.001);
}
for (j in 1:2) {
b1[j] ~ dnorm(0,.001);
prec[j] <- pow(sigma[j],-2);
sigma[j] ~ dunif... | g68644 | [
-0.009160567075014114,
-0.012025109492242336,
0.001730924122966826,
-0.046804506331682205,
0.044068027287721634,
-0.023729553446173668,
0.05029432475566864,
-0.012360475957393646,
-0.04917766898870468,
-0.03134387731552124,
-0.013266417197883129,
0.06298051029443741,
-0.005306740757077932,
... |
<p>I am a software developer (mostly .NET and Python about 5 years experience). What can I do to help me get a job in the machine learning field or really anything that will get me started in that field? Is post-graduate degree a hard requirement?</p> | g28740 | [
-0.04567914456129074,
0.01814357563853264,
0.04049544036388397,
-0.02498137205839157,
0.01237895991653204,
0.02906937710940838,
-0.02328977920114994,
0.013258523307740688,
-0.02655310370028019,
-0.03065364621579647,
-0.07605289667844772,
0.004838506691157818,
0.04633496329188347,
0.0293229... |
<p>Whenever I see people using ngrams - I often see them looking for higher chains like 4-grams, 5-grams and so on. However, I'm wondering why I never see any mention of "nested ngrams" (I'm not sure what the real name is).</p>
<p>For example, suppose you tracked the bigram "to follow" followed by the bigram "after da... | g41065 | [
-0.0018166203517466784,
0.08382342010736465,
-0.00024237630714196712,
0.044274214655160904,
-0.00361362611874938,
-0.08092796057462692,
0.05629377439618111,
-0.019365396350622177,
-0.06468640267848969,
-0.06948048621416092,
-0.012246541678905487,
0.00880997721105814,
0.045659031718969345,
... |
<p>When using NNs for estimation purpose, we have three layers: input, output and hidden layer, and we must choose the number of nodes for every layer.
Is there a method or rule of thumb to choose the correct number of nodes?</p> | g28742 | [
0.021683797240257263,
0.0689108669757843,
0.015453513711690903,
-0.010646513663232327,
-0.012762472033500671,
-0.05390114337205887,
0.0063733565621078014,
-0.008084080182015896,
-0.03268813714385033,
0.004167988430708647,
-0.04792698472738266,
-0.007709368132054806,
0.02577846124768257,
0.... |
<p>In the statistical practice of experimental design, you separate your tests by 'blocks' if you can control the factors (say routing to one page or another, or categorizing by browser) or through randomization of trials to counteract variables you don't control.</p>
<p>When doing A/B testing, you obviously can't con... | g68645 | [
-0.0377202183008194,
0.051916975528001785,
0.0010393483098596334,
-0.004350146744400263,
0.02349814586341381,
-0.04576331377029419,
0.056220583617687225,
0.04978235810995102,
0.044030651450157166,
-0.016222966834902763,
0.0431140698492527,
-0.022442637011408806,
0.062011558562517166,
0.012... |
<p>I would like to perform reversible jump on a network model, but before arriving there, I'm wondering if there are any R packages which support reversible jump for a user specified generalized linear model or spatial-GLM?</p>
<p>Something as simple as an RJMCMC procedure (in R) for the selection of predictors in a l... | g28746 | [
0.04044326767325401,
-0.020209375768899918,
-0.0046745832078158855,
-0.001037680427543819,
-0.01660982146859169,
-0.04480234906077385,
0.04925118014216423,
0.021381370723247528,
-0.04170329496264458,
-0.023673413321375847,
0.010150887072086334,
0.02619502879679203,
0.06555523723363876,
-0.... |
<p>When programming in R, I've used the <a href="http://www.rforge.net/doc/packages/multicore/multicore.html" rel="nofollow">multicore</a> package a few times. However, I've never seen a statement about how it handles it's random numbers. When I use openMP with C, I'm careful to use a proper parallel RNG, but with R I'... | g68646 | [
0.0008760304772295058,
0.016716402024030685,
-0.0006069501396268606,
-0.023762406781315804,
0.03366167098283768,
-0.07146954536437988,
0.039849527180194855,
0.031176691874861717,
-0.006072756368666887,
-0.03105422854423523,
-0.05342939496040344,
-0.023636670783162117,
0.027713973075151443,
... |
<p>I have 3 factors
factor1 (treatment) with 2 levels (control, stress)
factor2 (Variates) with 12 Levels (Var1, Var2,....Var12)
factor3 (Time) with 12 levels (Week1, Week2,..., Week12)</p>
<p>The treatment has 3 replicates for control and 6 replicates for stress.
Would it be unbalanced Design?
What design would you ... | g68647 | [
-0.019124750047922134,
-0.01278594508767128,
-0.03626279532909393,
-0.04404698312282562,
0.009184315800666809,
-0.010603183880448341,
-0.003559952136129141,
0.006518269889056683,
-0.003824049374088645,
-0.005068250000476837,
0.002447170438244939,
0.014730069786310196,
-0.00018952575919684023... |
<p>Which inter-rater reliability methods are most appropriate for ordinal or interval data?</p>
<p>I believe that "Joint probability of agreement" or "Kappa" are designed for nominal data. Whilst "Pearson" and "Spearman" can be used, they are mainly used for two raters (although they can be used for more than two rate... | g68648 | [
0.025183716788887978,
-0.00967161450535059,
-0.001246359315700829,
-0.02952059917151928,
-0.014065243303775787,
0.003285957733169198,
-0.011949912644922733,
0.008729376830160618,
-0.05097948759794235,
0.009059373289346695,
0.06080518290400505,
0.02470019832253456,
-0.008958625607192516,
-0... |
<p>I have been debating between a model-based parametric clustering approach (e.g. HMMs), and a hierarchical Dirichlet/Pitman-Yor process for clustering sequential data. I understand the latter has been very popular in the recent past (no model selection, heavy tails, etc.), but I could not find any analysis of how it ... | g68649 | [
0.05958456173539162,
0.01525014080107212,
0.006483865436166525,
-0.016620703041553497,
-0.01860082894563675,
-0.05964697524905205,
0.0333043672144413,
-0.009703759104013443,
-0.03342944011092186,
-0.04406062886118889,
-0.008367893286049366,
-0.019367875531315804,
0.065093033015728,
-0.0095... |
<p>I am currently working on my thesis and interested in estimating a Weibull conditional Hazard Frailty Model for recurrent event data using WinBUGS. I wrote the model but when am trying to use it with the following script it hangs unexpectedly. It returns a messages titled "undefined real result". What am I doing wro... | g68650 | [
-0.013524845242500305,
-0.05288669466972351,
0.015786875039339066,
-0.04790504649281502,
0.003960013389587402,
-0.0005003166734240949,
0.010572192259132862,
-0.0013719327980652452,
-0.06594400107860565,
-0.07427546381950378,
-0.004825431853532791,
0.04152422398328781,
0.04428892210125923,
... |
<p>I have customer feedback data about 2-3 products from 100 customers. Number of questions are around 160. I have data in excel format. Header row contains the question and row below contains the responses from customers. Not all questions have been answered by each customer. I have to categorize the feedback as eith... | g68651 | [
0.027491211891174316,
-0.03702167794108391,
-0.009202473796904087,
0.01060327049344778,
0.032979566603899,
-0.01689079962670803,
0.022716064006090164,
0.005857810378074646,
-0.06728281825780869,
-0.03373543173074722,
0.029473621398210526,
0.0216207355260849,
0.03128134831786156,
-0.0010897... |
<p>I have created a multiple linear regression model to predict prices and about 17% of the predicted prices have come out to be negative. Is there a way to correct for this error, or does it mean that the independent variables are not good predictors? The R^2 coefficient is 0.865.</p> | g68652 | [
-0.007348477840423584,
-0.07548739016056061,
-0.0033744447864592075,
0.02186412923038006,
0.009420131333172321,
0.007169928401708603,
-0.02624952793121338,
-0.002114046597853303,
-0.05574590340256691,
0.02777157723903656,
-0.0014090898912400007,
0.017376214265823364,
0.025637593120336533,
... |
<p>I have 15 subjects each with 200 trials & I'd like to run separate regressions for each subject.</p>
<p>If I just run the regression on the whole dataset I am able to generate odds ratios / confidence intervals from it:</p>
<pre><code>acc.log = glm(response ~ phdot + sdot, data=fullerr, family="binomial")
summ... | g68653 | [
0.040682729333639145,
-0.04251349717378616,
-0.04506249353289604,
-0.03435336798429489,
-0.025372186675667763,
-0.005460717249661684,
0.04266360402107239,
0.017736701294779778,
-0.051832426339387894,
-0.05282975733280182,
-0.0032290888484567404,
-0.012602915056049824,
0.03273657709360123,
... |
<p>So for instance here are the definitions that I get from standard text books</p>
<p>Variable - characteristic of population or sample.
ex. Price of a stock or grade on a test</p>
<p>Data - actual observed values</p>
<p>So for a two column report [Name | Income] the column names would be the variables ... | g68654 | [
0.036019466817379,
-0.03417748585343361,
-0.016695242375135422,
-0.08077128231525421,
0.028637539595365524,
-0.0034473161213099957,
-0.008889512158930302,
-0.008751831948757172,
-0.05121231451630592,
0.005877211689949036,
0.060219258069992065,
-0.012802386656403542,
0.03034333884716034,
-0... |
<p>I'd like to review the results of a recent survey I conducted. I'd like to see how one set of answers may/may not have influenced another set of answers. </p>
<p>For example:</p>
<p>If users who answered question #1 on a 1-8 Likert scale with answers from 6-8, does this correlate to how they answered questions 2... | g28750 | [
-0.03125815466046333,
-0.011268126778304577,
0.0062666358426213264,
-0.025414953008294106,
0.01910804770886898,
-0.018577944487333298,
0.027443837374448776,
-0.042314108461141586,
0.01933746412396431,
-0.028175007551908493,
0.03167754039168358,
0.011355758644640446,
0.020210981369018555,
0... |
<p>Let's say I have four variables $x_1, x_2, x_3$ and $x_4$ all distributed as Poisson, with means $\lambda_i$, and standard deviations respectively. Now I want to calculate two further variables $y_1= \frac{x_1}{x_2}$ and $y_2 = \frac{x_3}{x_4}$.</p>
<p>Finally I have a function $f(y_1, y_2)=(y_1-n)/(y_2-m)$.</p>
<... | g28753 | [
0.03350125998258591,
-0.02742997743189335,
-0.034836579114198685,
-0.012911368161439896,
-0.004787319805473089,
-0.004524851217865944,
-0.017922058701515198,
0.004825905431061983,
-0.08875968307256699,
-0.05646219477057457,
-0.06168142333626747,
0.0025044509675353765,
-0.0013499963097274303,... |
<p>I'm a beginner when it comes to support vector machines. Are there some guidelines that say which kernel (e.g. linear, polynomial) is best suited for a specific problem? In my case, I have to classify webpages according to whether they contain some specific information or not, i.e. I have a binary classification pro... | g68655 | [
0.03956747055053711,
0.04344760999083519,
0.019336599856615067,
-0.02348857745528221,
0.002475222572684288,
-0.07636917382478714,
-0.03777206316590309,
0.011426233686506748,
-0.058379583060741425,
-0.02455219253897667,
0.0730055496096611,
0.024099847301840782,
0.04158133268356323,
0.048105... |
<p>I am trying to understand how to obtain $p$-values for the <a href="http://stats.stackexchange.com/questions/107668/does-it-make-sense-to-perform-a-one-tailed-kolmogorov-smirnov-test"><em>one-sided</em> Kolmogorov-Smirnov test</a>, and am struggling to find CDFs for $D^{+}_{n_{1},n_{2}}$ and $D^{-}_{n_{1},n_{2}}$ in... | g68656 | [
-0.052139561623334885,
0.005270219407975674,
-0.04054045304656029,
-0.008947952650487423,
0.030467497184872627,
-0.04680153355002403,
0.05306621640920639,
0.0154365673661232,
0.001478136982768774,
-0.025073492899537086,
-0.04457506909966469,
0.010782698169350624,
0.02230183407664299,
0.023... |
<p>I have a problem considering the length of the <em>y</em>-axis in a LOWESS plot in Stata. The <em>y</em> variable ranges from 0 to 50. I would like to run the LOWESS on all the data but only display the graph for the range of <em>y</em> from 30 to 50. I've searched throughout the net, but I just found that I would a... | g68657 | [
0.04186064749956131,
0.05937276780605316,
-0.029916128143668175,
-0.02801012434065342,
-0.053886331617832184,
-0.027752483263611794,
0.018985247239470482,
-0.06101188436150551,
-0.0007344420882873237,
-0.017006732523441315,
0.05229775980114937,
0.09881069511175156,
0.06187764182686806,
-0.... |
<p>I am curious to know whether central-limit theorem like considerations hold true for special functions like the norm of a matrix.</p>
<p>Specifically, I'm interested in the <a href="http://mathworld.wolfram.com/SpectralNorm.html" rel="nofollow">Spectral norm</a> of a matrix
$$\|M^\prime\| = \text{Max eigenvalue of... | g28756 | [
0.012977332808077335,
0.01722768135368824,
-0.010589337907731533,
-0.04402850940823555,
-0.05599270761013031,
-0.02376672811806202,
-0.002091778442263603,
-0.009377149865031242,
0.02325037494301796,
0.0161117073148489,
-0.0051591177470982075,
0.01752667874097824,
-0.03165711462497711,
0.00... |
<p>Is it possible to perform a power analysis for the Kruskal-Wallis and Mann-Whitney U test? If yes, are there any R packages/functions that perform it?</p> | g68658 | [
-0.04172089323401451,
-0.03131475672125816,
0.005831979680806398,
0.006197454873472452,
-0.039538267999887466,
-0.03337233141064644,
-0.039590463042259216,
0.010210161097347736,
-0.03656546398997307,
-0.0071307700127363205,
0.023620523512363434,
0.010464751161634922,
0.029510056599974632,
... |
<p>$$ Y_i = \sum_j B_{ij} X_j$$</p>
<p>$$ covar(X_i, X_j) = V_X = \delta_{ij} var(X_i)^2 $$</p>
<p>$$ covar(B_{ij},B_{kl}) \neq 0 $$</p>
<p>$$ V_Y = ? $$</p>
<p>I know, that if $B$ was fixed, it <a href="http://www.statlect.com/normal_distribution_linear_combinations.htm" rel="nofollow">is straight forward</a>, but... | g68659 | [
0.007724937982857227,
0.038887593895196915,
-0.032282836735248566,
-0.030566344037652016,
-0.0447332039475441,
-0.02180042676627636,
0.060272086411714554,
-0.017595630139112473,
-0.03461995720863342,
0.005892210640013218,
-0.010152210481464863,
0.03802959993481636,
0.025775494053959846,
0.... |
<p>This is the description of my study. I'm experimenting with three plants: A, B, and C. These plants are supposed to reduce blood glucose for diabetic patients. I want to determine which of these three plants has a longer effect on blood glucose reduction after a single administration into mice. This is done by measu... | g28759 | [
0.02539449743926525,
-0.014178921468555927,
0.00637098727747798,
-0.00916971080005169,
-0.021422235295176506,
-0.04263332486152649,
0.02641705796122551,
0.020674891769886017,
-0.08314286917448044,
0.037082500755786896,
0.04594054073095322,
0.050176121294498444,
0.022067099809646606,
0.0538... |
<p>Suppose that data <em>X</em> have a Normal distribution with some mean $\mu$ and some variance $\sigma^2$. However, you don't get to see <em>X</em>. Instead, you see $Y = g(X)$ where $g$ is a known function. Assume that $g$ is complicated and is not invertible. </p>
<p>How do you write the likelihood function f... | g68660 | [
0.013340639881789684,
-0.04276517033576965,
-0.01088691782206297,
-0.015232210047543049,
-0.00022612694010604173,
0.006070778705179691,
0.03536427766084671,
0.04730164259672165,
-0.06050653010606766,
-0.025171872228384018,
0.002930294955149293,
0.017384720966219902,
0.05384493246674538,
0.... |
<p><em>I have got an answer for it from Spacedman. But I am not entirely satisfied with the answer as it does not give me any sort of value (p or z value). So I am re-framing my question and posting it again. No offences to Mr.Spacedman.</em></p>
<p>I have a dictionary of say 61000 elements and out of this dictionary,... | g49452 | [
-0.017071833834052086,
0.069359190762043,
-0.00460378173738718,
-0.02475893497467041,
-0.022457340732216835,
0.0020790956914424896,
0.03903014212846756,
0.045117415487766266,
0.015111644752323627,
0.015706470236182213,
-0.019179580733180046,
0.02943672239780426,
0.046669814735651016,
0.018... |
<p>I found a new use of a drug already in use. The results are as follows.</p>
<p>Serail No. of Patient-- Attacks while on Placebo-- Attacks while on drug --Difference in the no. of attacks</p>
<p>1- 23- 2- 21</p>
<p>2- 17- 1- 16</p>
<p>3- 13- 3- 10</p>
<p>4- 26- 0- 26</p>
<p>5- 16- 0- 16</p>
<p... | g68661 | [
-0.009315615519881248,
-0.008882872760295868,
-0.021679364144802094,
-0.06431671231985092,
0.06143796443939209,
-0.09022051841020584,
0.03676017001271248,
-0.024321703240275383,
-0.005650890059769154,
-0.007868098095059395,
0.014416811987757683,
0.047366973012685776,
0.031640611588954926,
... |
<p>I have done a ncvTest, but I am not really sure how to interpret this properly. I look documentation and examples online but was not able to find anything that clearly explains about ncvTest.</p>
<p>Here are my results from ncvTest:</p>
<pre><code>Non-constant Variance Score Test
Variance formula: ~ fitted.values... | g68662 | [
0.02741473913192749,
0.00443271966651082,
0.006491309963166714,
-0.0033456129021942616,
0.0266067273914814,
0.014875479973852634,
0.031130483373999596,
0.03125818073749542,
-0.010018033906817436,
-0.018962116912007332,
-0.06519633531570435,
0.023028571158647537,
-0.052439767867326736,
0.01... |
<p>I have about $10^6$ data vectors, each with 13 dimensions. I'm trying to train a GMM of 256 components using EM algorithm (using <a href="http://www.it.lut.fi/project/gmmbayes/" rel="nofollow">GMMBAYES</a>). Is there any rule of thumb about how many data points are generally sufficient to train a N dimensional, M co... | g28764 | [
-0.08137550950050354,
0.032917167991399765,
0.0019134399481117725,
-0.02092256024479866,
-0.02747073583304882,
-0.030666803941130638,
0.06344634294509888,
0.04828151315450668,
-0.051305823028087616,
0.003497338853776455,
-0.007860546000301838,
0.01247906219214201,
0.0038282363675534725,
0.... |
<p>I have noisy time series which I need to segment into those portions with a zero mean and those portions without a zero mean. Finding the boundaries as accurately as possible is important (clearly where the boundary precisely lies is a bit subjective). I think a cusum variant could be adapted to do this but as cusum... | g28765 | [
0.04380768910050392,
0.02169037237763405,
0.011920095421373844,
-0.04251227527856827,
-0.04180610179901123,
-0.09086839109659195,
0.029971182346343994,
0.023285681381821632,
-0.007463923189789057,
0.008141943253576756,
0.014265932142734528,
0.006959115155041218,
0.0044307284988462925,
0.00... |
<p>I am working on a web based project that will track a person's symptoms and drugs and nutrients they intake. For example thyroid patients symptoms of fatigue vs the dose of thyroid and also how much selenium, iodine, vitamin A, protein, etc they get from food or supplements. </p>
<p>I've added a basic set of desc... | g68663 | [
0.009003587998449802,
0.02951953001320362,
-0.019549498334527016,
-0.0024737324565649033,
-0.03951074555516243,
-0.07405972480773926,
0.03428706154227257,
-0.000049161037168232724,
-0.015751909464597702,
-0.027365203946828842,
0.022935526445508003,
0.0044374312274158,
0.08127427846193314,
... |
<p>I'm working on an extended Cox proportional hazards regression model which is predicting a recurrent event, inpatient hospitalization, during a 2 year period and will include multiple time-varying covariates (at least 10). </p>
<p>My understanding is that the counting process method incorporates multiple records pe... | g68664 | [
0.0010497840121388435,
0.007357513532042503,
0.004048301372677088,
-0.021985827013850212,
0.023656435310840607,
-0.0014600473223254085,
-0.034451067447662354,
0.018633531406521797,
-0.03385176509618759,
0.0018449353519827127,
0.002798339817672968,
-0.015906786546111107,
0.04538794234395027,
... |
<p>Apart from k nearest neighbour and its variants like fast K NN, what are the other search algorithms? I tried googling and reading but I did not get any effective answer. I am aware of binary search, heap search, simulated annealing, tabu search. But I do not know what are the time complexities and was looking for ... | g16463 | [
0.04892206937074661,
0.029144717380404472,
0.008891332894563675,
0.016285894438624382,
-0.003131419187411666,
-0.036977674812078476,
-0.04770825803279877,
-0.0019273750949651003,
-0.02334429882466793,
0.026555057615041733,
-0.0015342787373811007,
-0.0047241030260920525,
0.025496095418930054,... |
<p>Recently I’ve been working on a logistic model and I´m having some difficulties evaluating the results. I am still learning all this, so I apologise in advance for the mistakes. I would still appreciate any insight though.</p>
<p>So, my model is a binomial logit. My explanatory variables are: 1 categorical variable... | g68665 | [
-0.05632612854242325,
0.000049331032641930506,
-0.007292583584785461,
-0.008791513741016388,
0.02057853899896145,
-0.014069389551877975,
0.07608854025602341,
0.025219079107046127,
-0.017349567264318466,
0.01111996453255415,
0.006722342222929001,
0.022728847339749336,
0.047655120491981506,
... |
<p>I'm trying to run this two-part model in JAGS. I have two components, one logit and one lognormal regressions in there:</p>
<pre><code>model {
# Lognormal regression model
for (i in 1:N) {
for (j in 1:M) {
y[(i-1)*8+j] ~ dlnorm(mu[(i-1)*8+j], prec.y)
mu[(i-1)*8+j] <- beta0 + delta1[i] + del... | g68666 | [
0.009709363803267479,
-0.025594567880034447,
0.008589141070842743,
-0.0516323484480381,
0.04730668291449547,
-0.03792209178209305,
0.01108485832810402,
-0.028993241488933563,
-0.02859637700021267,
-0.03208572044968605,
0.03765476867556572,
0.05200352147221565,
0.004165933467447758,
-0.0034... |
<p>In MATLAB, I've written two snippets of code that compute the PDF of a multivariate normal distribution. However there's a difference in the values these two methods produce and I can't figure out why. I've narrowed the problem down to something having to do with computing the inverse of the covariance matrix.</p>
... | g28769 | [
0.042549293488264084,
-0.06713928282260895,
0.005945932120084763,
-0.04330625757575035,
0.031396716833114624,
0.0174479391425848,
0.027529533952474594,
0.010728162713348866,
-0.0865054577589035,
0.010146725922822952,
-0.00025952092255465686,
0.05372428521513939,
0.02080606296658516,
-0.011... |
<p>I've got 2 treatment groups with 2 possible outcomes when tested (positive or negative). I also have different time points for the testing. Is there anyway I can analyze if the change from positive to negative is significant between treatment at a given period of time? Thanks!</p> | g37718 | [
-0.05735963582992554,
-0.024853525683283806,
-0.01468536164611578,
0.01678146980702877,
0.02381432242691517,
-0.03211011365056038,
-0.014258956536650658,
0.007028489839285612,
-0.062361594289541245,
0.04855833575129509,
0.0411498099565506,
0.05807564780116081,
0.015549484640359879,
0.02755... |
<p>I have a data frame of chemical concentrations that are measurements taken from 12 locations all in the same vicinity. I have manually assigned x and y coordinates to each location (on a 0 to 20 scale) and each observation has a concentration value. a small sample is given below:</p>
<pre><code>dat<-data.frame(x... | g68667 | [
0.01657283864915371,
-0.027350744232535362,
-0.019292457029223442,
-0.07055211812257767,
-0.07185061275959015,
-0.04602725803852081,
0.05055166035890579,
-0.03686090558767319,
-0.0828026533126831,
-0.023070111870765686,
0.08053508400917053,
0.015828201547265053,
0.07226293534040451,
-0.000... |
<p>How do you use MGF for solving moment based questions for multivariate random variables?</p>
<p>For the single variable case, we:</p>
<p>find $E(e^{tX})$, find the interval in which it exists (around 0), differentiate it n times and plug in t as 0 to receive the n'th moment $E(X^n)$.</p>
<p>With a general multiva... | g28772 | [
0.006813304033130407,
-0.028384629637002945,
-0.014182429760694504,
-0.023192966356873512,
0.004233017098158598,
-0.0499250553548336,
0.027945782989263535,
0.0068051484413445,
-0.052348874509334564,
0.02810944803059101,
-0.03204209357500076,
-0.040394995361566544,
0.04056981950998306,
0.03... |
<p>I want to compare the strengths of different predictors (all at Level 1) using HLM and am not sure what statistical test would be appropriate. </p>
<p>More specifically, if I have 3 predictors at level 1 and I want to know which of them are statistically different from the others, what is the best way to do this?</... | g38729 | [
0.023141974583268166,
-0.057049673050642014,
0.009963146410882473,
0.026459449902176857,
-0.010361755266785622,
-0.03334575518965721,
0.011070269159972668,
0.021309802308678627,
-0.05969996750354767,
-0.028087757527828217,
0.04839610680937767,
-0.014111883006989956,
-0.005932072643190622,
... |
<p>I need some suggestions regarding what kind of metric and clustering analysis I should use. I read a lot of posts but didn't get any hints about this type of data. </p>
<p>I have a 3000*5000 matrix, where 3000 is signals from various different sources and 5000 is time point from 0 to 5000 seconds. for example: a s... | g848 | [
0.014605000615119934,
0.004424356855452061,
-0.02268172800540924,
-0.03612204268574715,
-0.036696769297122955,
-0.05501184239983559,
0.01937735266983509,
-0.02471591718494892,
-0.02745479717850685,
0.02064252272248268,
0.01973496563732624,
0.021982932463288307,
0.06502064317464828,
-0.0094... |
<p>Given a uniform random number generator (such as <a href="http://en.wikipedia.org/wiki/Linear_congruential_generator" rel="nofollow">the linear congruent method</a>), how shall I generate a sequence of i.i.d. random
samples? </p>
<p>Are samples generated in a successive sequence i.i.d., or
are they just rea... | g68668 | [
-0.0032495171763002872,
-0.0604906901717186,
-0.01083054207265377,
-0.08262805640697479,
-0.0520605593919754,
-0.03816266730427742,
-0.006360605824738741,
0.039503879845142365,
-0.06277445703744888,
-0.049748897552490234,
-0.04145357012748718,
0.005098016932606697,
-0.014407959766685963,
0... |
<p>I am no statistical geek and this might be a very naive question.....I am sorry before hand... please share your knowledge.</p>
<p>I am bit confused between two terms <strong>Canonical Correpondence Analysis</strong> and <strong>Canonical Correlation Analysis</strong>. </p>
<p>Are the two some how related or they ... | g68669 | [
0.08677245676517487,
-0.08497056365013123,
0.04263658449053764,
-0.015889441594481468,
-0.00814812257885933,
0.019043708220124245,
0.03636977821588516,
0.06625521183013916,
-0.008726746775209904,
-0.05604468658566475,
-0.004513469524681568,
-0.010559231042861938,
0.025577064603567123,
0.03... |
<p>I have a set of data points, which exhibit a solid linear correlation $r\approx 0.9$. I am basically plotting population in certain areas against the number of occurrences of a certain phenomenon (so in other words, I think the number of people should predict the number of occurrences of this phenomenon).</p>
<p>I ... | g68670 | [
0.01958390325307846,
-0.011331665329635143,
-0.00315503915771842,
-0.03976648673415184,
0.005186251364648342,
-0.03354280814528465,
0.05689012259244919,
0.008953232318162918,
-0.058943044394254684,
-0.07027899473905563,
0.0014275392750278115,
0.040976982563734055,
0.08276592940092087,
-0.0... |
<p>Suppose $$
z_i \sim Bernoulli (p_i)
$$</p>
<p>Can we use CLT for the following weighted sum? </p>
<p>$$
S = \sum_i w_i z_i
$$</p>
<p>i.e. can $S$ be approximated with a normal distribution? If yes, with which theorem? (I suppose the classical CLT holds only for average of iid variables)</p> | g68671 | [
0.035776831209659576,
0.002284429734572768,
-0.01494524721056223,
-0.008830375969409943,
-0.0458441786468029,
-0.01547632459551096,
-0.008564085699617863,
-0.052882660180330276,
-0.02370290271937847,
0.00923222303390503,
-0.03402761369943619,
0.06282475590705872,
-0.001401210087351501,
0.0... |
<p>I am trying to fit a model to predict a quantitative response variable, using several binary variables. In particular, I am interested in measuring the relationship between one of the binary variables and the outcome variable, holding the other binary variables constant.</p>
<p>My inclination is that ANOVA is the a... | g28774 | [
0.012392467819154263,
-0.007722750771790743,
0.013292684219777584,
0.027094367891550064,
-0.0405113510787487,
0.022188980132341385,
0.024901099503040314,
0.018238278105854988,
-0.03077465295791626,
-0.01475304365158081,
-0.012248042970895767,
-0.022546792402863503,
-0.023542476817965508,
0... |
<p>I want to calculate coefficients to a regression that is very similar to logistic regression (Actually logistic regression with another coefficient:
$$ \frac{A}{1 + e^{- (b_0 + b_1 x_1 + b_2 x_2 + \ldots)}},$$
when $A$ could be given).
I thought of using GMM to calculate the coefficients, but I'm not sure what are... | g38738 | [
-0.018004626035690308,
-0.023193923756480217,
0.01928221993148327,
-0.02581917680799961,
0.047775749117136,
-0.05181344598531723,
0.01845974288880825,
-0.005308850202709436,
-0.07194974273443222,
0.028539098799228668,
-0.034304287284612656,
0.06397230178117752,
0.0431118942797184,
0.028478... |
<p>My question is regarding linear regression and non-constant variance. I've heard that even though a large data set fails a normality test, this does not necessarily mean the data is not normal. This is because the tests for normality can be 'overly' sensitive.' Thus, I've heard that, in practice, people overlook whe... | g28779 | [
-0.027549128979444504,
-0.006426357664167881,
0.019098034128546715,
-0.02155996672809124,
-0.025164809077978134,
0.027029789984226227,
0.03614949807524681,
0.0121607119217515,
-0.03437688201665878,
-0.05697495862841606,
0.01077705156058073,
0.05541197583079338,
-0.06160646304488182,
-0.060... |
<p>When calculating Cohen's $d$ for independent samples, you must use a pooled $SD$. However, I have seen both of these:</p>
<p>$$SD_{\text{pooled1}} = \sqrt{\frac{ (n_1 - 1)s_1^2 + (n_2 - 1)s_2^2}{n_1 + n_2}}$$</p>
<p>vs.</p>
<p>$$SD_{\text{pooled2}} = \sqrt{\frac{ (n_1 - 1)s_1^2 + (n_2 - 1)s_2^2}{n_1 + n_2 -2}}$$<... | g37469 | [
0.00999182928353548,
0.008090183138847351,
-0.019228441640734673,
-0.04607918858528137,
-0.03029225952923298,
-0.009387848898768425,
0.03377519175410271,
-0.008732958696782589,
-0.02277521975338459,
-0.007436756975948811,
0.008132006041705608,
0.04679408296942711,
0.0511787123978138,
0.015... |
<p>I would like to find the correlation between a continuous (dependent variable) and a categorical (nominal: gender, independent variable) variable. Continuous data is not normally distributed. Before, I had computed it using the Spearman's $\rho$. However, I have been told that it is not right.</p>
<p>While searchin... | g68672 | [
0.054499201476573944,
-0.03685585409402847,
-0.026921724900603294,
-0.05222225934267044,
-0.01846902444958687,
-0.007947945967316628,
0.017125893384218216,
-0.010922189801931381,
-0.0751444399356842,
0.0029626633040606976,
-0.03335811197757721,
0.015214844606816769,
0.02647952176630497,
-0... |
<p>I am wondering I may get some advice. </p>
<p>If I wanted to find the value of P(A|Ū), and have values for P(A|U), P(A) and P(U), is there any probability functions that I can use?</p>
<p>Many thanks once again.</p> | g68673 | [
0.001049067941494286,
0.007944961078464985,
-0.002997928997501731,
-0.016980711370706558,
0.006388481706380844,
-0.03825633227825165,
0.010779515840113163,
0.018459975719451904,
-0.022451126947999,
-0.044209010899066925,
-0.05086005851626396,
-0.007717495784163475,
0.04486764967441559,
0.0... |
<p>My question is about the best way to estimate the effect of a predictor on a dependent variable, while accounting for several other predictors that may correlate with the predictor of interest. I'm using a linear mixed-effects model, using the <code>lmer</code> function from the R <code>lme4</code> package. (Warning... | g68674 | [
-0.010646190494298935,
-0.04443337023258209,
0.006276301573961973,
-0.05396481230854988,
-0.023655753582715988,
-0.0007751553202979267,
0.06689831614494324,
0.02510485053062439,
-0.009471368975937366,
-0.036049436777830124,
0.05229272320866585,
-0.025102518498897552,
0.04228935018181801,
0... |
<p>A ski-hotel has the most guests in the third quarter in every year (check the data below after the four questions).<br>
Can you answer these four questions (every year has 4 values, the first is quarter one and the second is quarter two, the third is quarter three and the fourth is quarter four and it's from the 200... | g68675 | [
-0.027531875297427177,
0.026902107521891594,
0.020950188860297203,
0.008589690551161766,
-0.050513409078121185,
0.0380367711186409,
0.06048140674829483,
0.04584576189517975,
-0.05249003320932388,
0.014217101037502289,
0.02202453464269638,
-0.0003376855456735939,
0.017247140407562256,
-0.02... |
<p>I am confused on what I have read about the Mann whitney test. We are testing whether our actual data is the same as our projected data. We had been using the t-test until we realized the data might not be normal and we are using ~12 observations per sample. Therefore I started using the Mann Whitney test. </p>
<p>... | g49810 | [
0.03452877327799797,
-0.0025093944277614355,
0.04448343813419342,
-0.03537207096815109,
-0.022181179374456406,
-0.024394121021032333,
-0.011887455359101295,
0.024985691532492638,
-0.04128292575478554,
-0.025271771475672722,
0.06472418457269669,
-0.03680706024169922,
-0.00008863650145940483,
... |
<p>$\phi (t)=\sum_{n=0}^{\infty}e^{tn}\cdot \frac{\lambda^{n}}{n!}e^{-\lambda}$</p>
<p>$=e^{-\lambda}\sum_{n=0}^{\infty}\frac{(e^{t}\lambda)^{n}}{n!}$</p>
<p>$=e^{-\lambda+\lambda e^{t}}$ I'm confused here as how $\sum_{n=0}^{\infty}\frac{(e^{t}\lambda)^{n}}{n!}$ simplifies to $e^{\lambda e^{t}}$, can someone please ... | g68676 | [
-0.004065422341227531,
0.024455778300762177,
-0.018854381516575813,
-0.09025638550519943,
0.03965973109006882,
-0.041113462299108505,
0.03582565486431122,
0.04409386217594147,
-0.051395103335380554,
-0.016342803835868835,
-0.09706275165081024,
0.050672173500061035,
0.05854106694459915,
0.0... |
<p>I'm working with an organization that is using JMP in their analysis, and I can't tell from the description in <a href="http://www.jmp.com/support/help/The_Logistic_Fit_Report.shtml#65559">JMP's help files</a> if the test for goodness of fit in their logistic regression is the Hosmer-Lemeshow test. If it makes a dif... | g28791 | [
0.032708507031202316,
-0.009692342951893806,
0.015311965718865395,
-0.019679028540849686,
0.014405607245862484,
-0.023631347343325615,
0.013461252674460411,
0.022140564396977425,
-0.05159839242696762,
-0.015214118175208569,
0.010843674652278423,
-0.006473602261394262,
0.04210507497191429,
... |
<p>I am wondering I may get some advice if P(A|Ū) is equals to 1- P(A|U)?</p>
<p>Many thanks once again.</p> | g28792 | [
-0.022972021251916885,
0.029295092448592186,
-0.021556105464696884,
-0.013695234432816505,
0.03499957546591759,
-0.03511670604348183,
0.026097267866134644,
0.0169349517673254,
0.03241221234202385,
0.014922448433935642,
-0.06325917690992355,
0.04873795062303543,
-0.03978987783193588,
0.0361... |
<p>I have this problem on what model class (AR,MA,ARMA,ARIMA,etc) will I use on my data I'm using Box-Jenkins process and what order( say 1,0,1) will I use. I already done many transformations on my data but the errors are so large and the correlation is somewhat small. My data are stationary using (ADF test and KPSS ... | g68677 | [
0.01638489030301571,
-0.05258561298251152,
-0.003832356072962284,
-0.02509581483900547,
0.04246746376156807,
-0.02609214000403881,
0.09252795577049255,
-0.004660379607230425,
-0.021002035588026047,
-0.048681821674108505,
0.011173849925398827,
0.0374099500477314,
0.08700402081012726,
-0.024... |
<p>I've seen the following question asked and answered many times on various forums:</p>
<blockquote>
<p>Knowing that the odds of rolling a six with one die are one in six, what
are the odds of rolling a six in two, three, four (etc.) consecutive rolls? 1/6 + 1/6 + ... wouldn't make sense as you'd have a 100% chan... | g68678 | [
0.009163799695670605,
0.026717346161603928,
0.040541235357522964,
0.040488261729478836,
-0.026887424290180206,
-0.07093493640422821,
0.015400550328195095,
0.04036454111337662,
-0.015537743456661701,
-0.02744533307850361,
-0.04808581992983818,
0.03255026787519455,
0.05423034355044365,
-0.00... |
<p>Inspired by a comment from <a href="http://stats.stackexchange.com/questions/14721/how-is-the-bayesian-framework-better-in-interpretation-when-we-usually-use-uninf">this question</a>:</p>
<p>What do we consider "uninformative" in a prior - and what information is still contained in a supposedly uninformative prior?... | g68679 | [
0.04487689584493637,
-0.025582486763596535,
0.0045936801470816135,
-0.09395438432693481,
-0.0249199029058218,
0.013570399023592472,
0.03192088380455971,
0.006704656407237053,
-0.0461210198700428,
-0.09528215229511261,
0.05508023872971535,
-0.0031047656666487455,
0.034996915608644485,
0.022... |
<p>I am using the Zero-trick to create a prior for correlation parameter. Data <code>y</code> is a bi-variate normal with covariance matrix with same diagonal elements and correlation phi. The covariance matrix is positive definite for <code>|phi| < 1</code>, the usual range for correlation. But instead of common pr... | g68680 | [
-0.039472050964832306,
-0.01766141876578331,
0.00816416647285223,
-0.07851969450712204,
0.04010048881173134,
-0.007209841161966324,
0.04561437666416168,
0.02104058675467968,
-0.009249663911759853,
-0.024453580379486084,
0.019821595400571823,
0.04142928868532181,
-0.028306910768151283,
-0.0... |
<p>I'd like to know if it is reasonable to use the same set of data to estimate and use a reliability metric from repeated measures? I am mostly interesting by the minimal detectable change (MDC). But I thought that the MDC was a property of a measuring instrument BEFORE using that instrument. Is that wrong? </p>
<p>I... | g28795 | [
0.025693826377391815,
-0.06519866734743118,
-0.005948387552052736,
-0.024169927462935448,
-0.03227563574910164,
-0.03439809009432793,
0.013402861542999744,
-0.01476352009922266,
-0.023847024887800217,
-0.049600809812545776,
-0.023502973839640617,
0.03102577105164528,
0.005905603989958763,
... |
<p>Regularized generalized linear mixed models and generalized additive mixed models are exactly what I need. I'm an R user, so it looks like <code>bGAMM</code> and maybe <code>glmmLASSO</code> are possibilities outside of doing my own implementation (which I don't have time to do for this project). My question is whet... | g28797 | [
-0.01954932138323784,
-0.018379712477326393,
-0.010951886884868145,
0.005845343228429556,
-0.00682295486330986,
-0.05471555516123772,
0.04710107669234276,
0.031220482662320137,
0.013835238292813301,
-0.022453509271144867,
-0.021792707964777946,
0.010841847397387028,
0.03183673694729805,
0.... |
<p>Is there a canonical textbook or textbooks on the use of numerical methods in solving stochastic differential equations that you would recommend?</p> | g38216 | [
0.06262966245412827,
-0.017763735726475716,
0.029300425201654434,
-0.013222383335232735,
-0.01746167242527008,
-0.01859571598470211,
0.010984218679368496,
0.02713175304234028,
-0.014698748476803303,
0.035609494894742966,
0.055728815495967865,
0.010897142812609673,
0.06867767870426178,
0.00... |
<p>For two $n$ dimensional multivariate normal distributions $X_{1}\sim N\left(\mu_{1},\Sigma_{1}\right)$
and $X_{2}\sim N\left(\mu_{2},\Sigma_{2}\right)$, the Kullback-Leibler distance is given by $$KL=\frac{1}{2}\left(tr\left(\Sigma_{2}^{-1}\Sigma_{1}\right)+\left(\mu_{2}-\mu_{1}\right)'\Sigma_{1}^{-1}\left(\mu_{2}-... | g38746 | [
0.03043586015701294,
-0.054491862654685974,
-0.001228500623255968,
-0.0013314896496012807,
-0.04805850610136986,
0.010517330840229988,
0.013368220999836922,
-0.039062175899744034,
0.022864436730742455,
0.06267546862363815,
0.014370009303092957,
-0.02503807842731476,
-0.0046599432826042175,
... |
<p>What is the difference between the <a href="https://en.wikipedia.org/wiki/Logit">logit</a> and the <a href="https://en.wikipedia.org/wiki/Probit">probit</a> model?</p>
<p>I'm more interested here in knowing when to use logistic regression, and when to use probit. If there's any literature which define it using <a h... | g49590 | [
-0.005474953446537256,
0.023435214534401894,
-0.012631259858608246,
-0.035395603626966476,
0.0640534833073616,
-0.0455457977950573,
0.01321345940232277,
0.017235971987247467,
-0.07216004282236099,
-0.04003457725048065,
0.013599183410406113,
-0.007943304255604744,
0.06246460974216461,
-0.03... |
<p>I want to model the number of users of an mobile app. This app has two kinds of users: <em>free</em> and <em>paid</em>. I thought of this autoregressive model:</p>
<p>$x_t = Ax_{t-1}$</p>
<p>with $x_t$ being a 4-dimensional vector, with quantities (all in period $t$) for the numbers of</p>
<ul>
<li>mobile users</... | g68681 | [
0.004725135862827301,
-0.017050467431545258,
-0.00987656507641077,
-0.02549649588763714,
-0.03729366138577461,
-0.023428890854120255,
0.045631539076566696,
0.004883877467364073,
-0.03924642875790596,
0.05982816219329834,
-0.009387149475514889,
0.020656034350395203,
0.10109831392765045,
0.0... |
<p>I'd like to make a prediction about a subject's likelihood that a certain outcome will occur based on a series of measurements taken over time. </p>
<p>The easiest way to explain the problem is as follows. Imagine that I'm tracking an individual over time to generate a probability of ever getting lung cancer.</p>
... | g68682 | [
-0.004457064904272556,
-0.04882601276040077,
0.02358866110444069,
-0.02695465087890625,
-0.034776754677295685,
0.00362115865573287,
0.038055382668972015,
0.020070776343345642,
-0.03077959455549717,
-0.045638106763362885,
0.0003075026615988463,
-0.019001945853233337,
0.0441240593791008,
-0.... |
<p>serve speed of a particular player was 102 miles per hour (mph)and the standard deviation of the serve speeds was 13 mph. Assume that the statistician also gave us the information that the distribution of the serve speeds was mound-shaped and symmetric. What proportion of the player's serves was between 89 mph and 1... | g49811 | [
0.022525770589709282,
0.028086787089705467,
-0.028329599648714066,
-0.04551566392183304,
0.011992485262453556,
-0.023215819150209427,
0.04953213781118393,
0.027180403470993042,
-0.04106028005480766,
0.023487403988838196,
0.011016386561095715,
-0.0010590500896796584,
0.03546062484383583,
-0... |
<p>I have a model:</p>
<p>$y=a+bx+\varepsilon_1$ for each observation (tree)</p>
<p>$b=c+dz+\varepsilon_2$ for each forest (group of trees)</p>
<p>$y$, $x$, $z$ are continuous variables. $a$, $b$, $c$, $d$ are coefficients. $z$ is a property of forests (not individual trees). Error $\varepsilon_1$ is normally distri... | g68683 | [
-0.03053220361471176,
-0.07085052132606506,
-0.012539800256490707,
0.0051650553941726685,
0.04028260335326195,
-0.027357513085007668,
0.03940523788332939,
0.007471978664398193,
-0.07247737050056458,
0.03661789745092392,
-0.015183117240667343,
0.003232805524021387,
-0.019373316317796707,
0.... |
<p>I am working on a research topic where I need to add together two AR processes and I was wondering if the distribution of these processes is of a recognizable form/structure. More formally, if $x_t$ is a AR(p) process with characteristic polynomial $\Phi_x(u)$ and $y_t$ is a AR(q) process with characteristic polyno... | g68684 | [
0.07115813344717026,
-0.03224325552582741,
-0.003352997126057744,
-0.016429774463176727,
0.02815777249634266,
-0.046022843569517136,
0.025432273745536804,
-0.02397988922894001,
0.05327203497290611,
0.02475699782371521,
0.010877901688218117,
0.04250127822160721,
0.055857088416814804,
-0.022... |
<p>Is there such a package that provides for zero-inflated negative binomial mixed-effects model estimation in R?</p>
<p>By that I mean:</p>
<ul>
<li><p>Zero-inflation where you can specify the binomial model for zero inflation, like in function zeroinfl in package pscl: <pre>zeroinfl(y~X|Z, dist = "negbin")</pre>
wh... | g68685 | [
0.008991396985948086,
-0.042745862156152725,
-0.0034834113903343678,
0.023621534928679466,
-0.039518196135759354,
-0.021804071962833405,
-0.022108109667897224,
0.03347492590546608,
-0.032743968069553375,
-0.03084852360188961,
0.0028065084479749203,
0.01856914907693863,
0.003746749833226204,
... |
<p>I would be <em>very</em> grateful for any ideas concerning the following problem. I would be even more grateful if someone could point me to a literature reference proposing a solution for a scenario like the one I describe below. In short, I am looking to adapt Bouackert and Frank's 2004 article on <a href="http://... | g68686 | [
-0.0057308305986225605,
-0.05297338590025902,
0.00003426528928685002,
-0.06274043768644333,
-0.0028902427293360233,
-0.04855410382151604,
-0.024668972939252853,
0.03749490901827812,
-0.07647471129894257,
0.0157199464738369,
0.02744431607425213,
0.025542473420500755,
0.04026218503713608,
0.... |
<p>Recently I've been building a model using logistic regression. To my suprisise LIFT chart looks better on the validation data than on the training data, the same is with ROC. All variables in the model are statistically significant. </p>
<p>The question is: Is this really a serious problem? If so, what are the meth... | g5572 | [
0.010121012106537819,
0.025468867272138596,
0.005737736821174622,
-0.037617966532707214,
0.03252436965703964,
-0.01228647492825985,
-0.001191373448818922,
0.07085269689559937,
0.006477638613432646,
-0.02765093930065632,
0.03977353870868683,
-0.016738831996917725,
0.033494241535663605,
0.00... |
<p>I have a small data set which contains two tissue samples from ~20 patients. Each patient has contributed a tissue sample from left and right hip joint. My aim is to study certain cell amounts in these samples. My aim is to investigate whether findings of the hips in each patients correlates, ie. that both hips have... | g68687 | [
0.009914873167872429,
-0.05935242772102356,
0.01776650734245777,
-0.04375282675027847,
-0.005628169514238834,
-0.023629873991012573,
0.030765149742364883,
0.02498408779501915,
-0.019722955301404,
-0.03378041088581085,
0.0450063981115818,
0.058734092861413956,
0.008343744091689587,
0.026946... |
<p>I am new in statistics, so maybe my question kind of stupid.<br/></p>
<p>I know how to evaluate the prediction performance if the label is binary, such as the classification label is <code>sick(yes/no)</code>. <br/></p>
<p>The situation is the label is <code>sick(level1/level2/level3)</code>,in this situation, cou... | g23877 | [
-0.0018203258514404297,
-0.05952181667089462,
0.008004152216017246,
-0.03394792228937149,
0.04328067973256111,
-0.035209834575653076,
0.03901137784123421,
0.038635510951280594,
-0.05768921598792076,
-0.045306313782930374,
-0.005607703235000372,
0.05307237058877945,
0.05369531363248825,
-0.... |
<p>I'm new to SVM and would like to use it to solve a problem formulated, for example, as follows:</p>
<p>The patterns are four-dimensional vectors $(x_1,x_2,x_3,x_4)$, and the kernel is $K(\bf{x_i}, \bf{x_j})=k1([{x_i}_1, {x_i}_2], [{x_j}_1, {x_j}_2]) \times k2([{x_i}_3, {x_i}_4], [{x_j}_3, {x_j}_4)$</p>
<p>In other... | g68688 | [
-0.004344415385276079,
0.04474344477057457,
0.015912365168333054,
0.0024922112934291363,
-0.03752020001411438,
-0.057732030749320984,
-0.022104276344180107,
-0.0249363724142313,
-0.0515906885266304,
0.03910788893699646,
0.005413506645709276,
-0.02696075476706028,
-0.009095629677176476,
0.0... |
<p>I have found discordant information on the question: "<strong>If one constructs a 95% confidence interval (CI) of a difference in means or a difference in proportions, are all values within the CI equally likely?</strong> Or, is the point estimate the most likely, with values near the "tails" of the CI less likely t... | g68689 | [
0.03304291144013405,
-0.029302997514605522,
-0.02038484998047352,
0.020423561334609985,
0.030069677159190178,
0.030480926856398582,
-0.005661576986312866,
0.01344909518957138,
-0.03078184835612774,
-0.016145048663020134,
0.0445135161280632,
0.02617587521672249,
0.01675393618643284,
-0.0025... |
<p>I consider a very simple example with two models like this;</p>
<pre><code>set.seed(66)
n <- 100
x <- rnorm(n,0,1)
y <- 10 + 2*x + rnorm(n,0,1)
mod1 <- lm(y ~ x)
mod2 <- lm(y ~ -1 + x)
</code></pre>
<p>I already checked the following: If I write down $r_{y\hat{y}}$ in Matrix notation with</p>... | g68690 | [
0.017668647691607475,
-0.04280708730220795,
-0.021895689889788628,
-0.04044942185282707,
-0.01648423634469509,
-0.05145207792520523,
0.059260688722133636,
0.012716742232441902,
-0.024476641789078712,
-0.021852770820260048,
-0.019596600905060768,
0.03604719042778015,
0.06599938124418259,
-0... |
<p>Background: I am using weighted non-linear regression to model the growth of plant organs, with dummy variables for different species. I am using a sum of squares reduction test (SSRT) to compare the parameter estimates of the model between the species in my study. For instance, for this logistic equation:</p>
<p>w... | g41453 | [
0.03232668340206146,
-0.05330853909254074,
-0.002042302628979087,
-0.0020718772429972887,
-0.023204941302537918,
-0.026474246755242348,
0.008739645592868328,
-0.03308985382318497,
-0.047424327582120895,
0.007568457163870335,
-0.025075701996684074,
0.0033796860370785,
0.02703029289841652,
0... |
<p>Is it possible to fit an ARIMA under a restriction that bounds the minimum to positive values? I'm using Minitab. </p> | g68691 | [
0.00006937451689736918,
0.01642744615674019,
0.024820668622851372,
0.021042997017502785,
-0.06821289658546448,
0.005315161310136318,
-0.034375376999378204,
-0.06222439184784889,
-0.06615013629198074,
-0.03329958766698837,
0.014854400418698788,
0.0008088552858680487,
0.05716005712747574,
-0... |
<blockquote>
<p>Suppose we're given data from three different classes which are normally distributed with the following means and variances:</p>
<p>$C_1: \mu_1=(1,2)^T, \Sigma_1^{-1}=( \begin{array}{ccc}2 & 1 \\1 & 2
\end{array})$<br>
$C_2: \mu_2=(2,-2)^T, \Sigma_2^{-1}=( \begin{array}{ccc}1 & 0 ... | g68692 | [
0.0075281476601958275,
-0.06959034502506256,
-0.012624528259038925,
-0.001465781475417316,
0.042422544211149216,
-0.005706870928406715,
0.019122393801808357,
-0.04349193722009659,
-0.054223302751779556,
-0.005135275423526764,
-0.002189405495300889,
0.055119406431913376,
0.049817103892564774,... |
<p>I found multinomial distribution really powerful in theory. But I don't know if my real case can be treated as multinomial. There are two cases:</p>
<ol>
<li>There are $n$ students, $30\%$ chose apple, $40\%$ chose banana, $30\%$ chose grape. Then can I say the choice of single student follow a $\mathrm{Multinomial... | g38769 | [
0.008886984549462795,
0.04015659913420677,
0.008486969396471977,
0.037394843995571136,
-0.021039273589849472,
-0.02212357707321644,
-0.039286378771066666,
0.0008952738135121763,
-0.004700728226453066,
0.04264822229743004,
-0.023676900193095207,
-0.09268373250961304,
-0.0172360111027956,
0.... |
<p>In decision theory, we define a reject option ($\theta$) so that when making decision is difficult, the case will be ignored. </p>
<p>Suppose $1/k \leq \theta \leq1$:</p>
<ul>
<li><p>If $\theta=1/k$ no cases will be rejected</p>
<p>and </p></li>
<li><p>If $\theta=1$ all cases will be rejected.</p></li>
</ul>
<p>... | g37441 | [
0.07692589610815048,
0.035869061946868896,
0.006976825650781393,
-0.02299603819847107,
-0.03272015601396561,
0.01761021465063095,
0.047606952488422394,
0.03825656697154045,
-0.031570594757795334,
-0.010238797403872013,
0.03395898640155792,
0.028740011155605316,
0.05726079270243645,
0.04106... |
<p>I have 108 counts taken from 36 field points. I took three counts from each point at different times, also, the 36 field points are divided in a altitude factor of three levels (12 points at each level). I have also six numerical independent variables measured at each count. I want to make a generalized linear model... | g38132 | [
0.005780817940831184,
-0.010566601529717445,
-0.025675032287836075,
-0.013715045526623726,
0.026748519390821457,
0.006050376687198877,
0.002746674232184887,
-0.0010940775973722339,
-0.05617499724030495,
-0.04239305853843689,
-0.05860248580574989,
0.02116190269589424,
0.04442499950528145,
-... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.