question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>We have a questionnaire measuring 9 clinical symptoms. The sum scores simply adds all these symptoms up. Symptoms are ordered (0,1,2,3), and pretty strongly skewed (lots of 0s). </p>
<p>1) First, we want to test whether the symptom configuration deviates from the Null-Hypothesis of all symptoms being equally severe... | g24227 | [
0.005809881258755922,
0.005473151337355375,
-0.019837459549307823,
-0.045080676674842834,
0.01833471655845642,
-0.06671763211488724,
0.03829781338572502,
0.03348787873983383,
0.026139887049794197,
-0.03413521498441696,
-0.018726620823144913,
0.010338439606130123,
0.04564700648188591,
-0.01... |
<p>Could anybody help me with detrending data that is nonstationary? I have already made the mistake of trying to detrend it by plotting the residuals of a linear regression in excel but it was pointed out to me by 'Zach' and 'cardinal' that it is not a valid method. Unfortunately, I had used that method after many hou... | g12984 | [
0.04871005937457085,
-0.022003300487995148,
-0.0012341212714090943,
-0.00023923121625557542,
-0.013597652316093445,
-0.016585102304816246,
0.009357990697026253,
-0.03861318156123161,
-0.10091415792703629,
-0.010026222094893456,
-0.014836168847978115,
0.07814019918441772,
0.017852971330285072... |
<p>I would like to test a hypothesis that a database contains data that are correct in 95% or more of the samples.</p>
<p>I found this <a href="http://stattrek.com/Lesson5/Proportion.aspx?Tutorial=AP" rel="nofollow">Hypothesis test for a proportion</a> experiment design that looked appropriate.</p>
<p>I will randomly... | g59407 | [
0.017967669293284416,
-0.0029281277675181627,
-0.023692796006798744,
-0.03952697291970253,
-0.014538994990289211,
-0.03994356095790863,
0.028431104496121407,
0.036747466772794724,
-0.03216956928372383,
0.005641930736601353,
0.0635315477848053,
-0.02936074510216713,
0.06624694913625717,
-0.... |
<p>Lets say we have three independent variables:<br>
$$\eqalign{
X_{1}\sim &B(n,\frac{1}{2}+\beta) \cr
X_{2}\sim &B(n,\frac{1}{2}) \cr
X_{3}\sim &B(n,\frac{1}{2}-\beta).
}$$</p>
<p>I'm looking for the distribution of </p>
<p>$$\max(X_{1},X_{2},X_{3})-\min(X_{1},X_{2},X_{3}).$$</p>
<p>For sufficientl... | g59408 | [
-0.022921644151210785,
0.020672142505645752,
-0.01653250679373741,
0.018717655912041664,
-0.002008437644690275,
-0.013579784892499447,
-0.02696649730205536,
0.007380883675068617,
-0.03953152522444725,
0.013439149595797062,
-0.032550811767578125,
0.04382706806063652,
-0.048287730664014816,
... |
<h3>Context:</h3>
<p>I'm investigating behaviour in a clinical study involving children. I had both parents and teachers completing questionnaires to inform an understanding of the same underlying constructs, for example reactive aggression. </p>
<p>At the conclusion of data collection I have parent data in all case... | g468 | [
0.06643202900886536,
-0.03562907502055168,
-0.016409846022725105,
-0.06255801767110825,
-0.0005313334404490888,
-0.037747371941804886,
0.016768738627433777,
0.017660794779658318,
-0.0030699926428496838,
-0.013152719475328922,
0.06237917020916939,
-0.03888234496116638,
0.02391458861529827,
... |
<p>The greatest gain of the statistics classes in both school and university seems to be that I now have an inkling of which QA site to use for this question. :)</p>
<p>I'm a programmer and I'm making a questionnaire with a financial background. There will be many (probably over 100) questions, which will be presented... | g59409 | [
0.026937764137983322,
0.0005259854369796813,
-0.015058579854667187,
-0.03373623639345169,
-0.0338454395532608,
-0.053889136761426926,
0.05872843787074089,
0.002323346910998225,
-0.01727679744362831,
0.004278188571333885,
-0.006074985954910517,
-0.005450536496937275,
0.034626126289367676,
0... |
<p>I'm attaching two sets I ran in SAS, regarding spline cubic regression models. </p>
<p>I'm new to stats and trying my best to learn but I'm stuck here. How do I get SAS to select outliers based on two or 3 standard deviations from the predicted value using the splines? </p>
<p>thanks</p>
<pre><code>options ls=75 ... | g59410 | [
0.023201409727334976,
-0.0859767347574234,
0.007444124668836594,
-0.04209522157907486,
0.002367757260799408,
-0.014259190298616886,
0.0643279030919075,
-0.008712803944945335,
-0.04294995963573456,
-0.031491246074438095,
0.008692976087331772,
0.0008421859820373356,
0.06806089729070663,
-0.0... |
<p>I am performing a retrospective study on patients looking at the size of their nostril (continuous variable measured in millimetres) and the need for treatment which is either conservative or surgical (this is a categorical variable).<br>
Sample size is only 15.</p>
<p>What would be the right test to compare groups... | g59411 | [
0.0010376578429713845,
0.011183902621269226,
0.0066309585236012936,
-0.07061613351106644,
-0.07065999507904053,
-0.06727156788110733,
0.0029650286305695772,
-0.01867576502263546,
0.024181272834539413,
-0.019535023719072342,
0.10141746699810028,
-0.00474675465375185,
0.00931172352284193,
0.... |
<p>I'm writing a benchmark program in C# and Java as a first assignment for a CS class. We're supposed to write some kind of report about our methods and results from the benchmark, and I'd like to add a statistical component to mine.</p>
<p>I've got 15 run time samples from each language, and the mean and standard de... | g94 | [
0.01510617882013321,
0.01163396891206503,
-0.003269653534516692,
-0.06578514724969864,
0.04552901163697243,
-0.04998292028903961,
0.03051954135298729,
-0.01137788686901331,
-0.08003026247024536,
-0.05142263323068619,
0.013586348854005337,
0.00961278472095728,
0.012293659150600433,
0.040741... |
<p>I have come across the sampling method called "Propensity Weighting Sampling/RIM", but I do not have a good idea of what these survey methods are all about. </p>
<p>What references in the literature cover this topic?</p> | g40801 | [
0.0704321637749672,
0.016810473054647446,
0.000596872647292912,
-0.03673523664474487,
0.021970387548208237,
-0.02746899425983429,
0.010575906373560429,
0.004525463562458754,
0.0035849609412252903,
-0.019835354760289192,
0.021080289036035538,
-0.03138364478945732,
0.06354768574237823,
0.018... |
<p>I have a table with four groups (4 BMI groups) as the independent variable (factor). I have a dependent variable that is "percent mother smoking in pregnancy". </p>
<p>Is it permissible to use ANOVA for this or do I have to use chi-square or some other test? </p> | g59412 | [
0.013335301540791988,
-0.0010668453760445118,
0.00005830193913425319,
-0.007720607798546553,
-0.037487637251615524,
-0.03964786231517792,
-0.010302510112524033,
-0.01624627225100994,
-0.0453849732875824,
0.005564205348491669,
0.025255640968680382,
0.03925764933228493,
-0.0034551366697996855,... |
<p>I am using regression tree to find the factors effecting food insecurity. I want to know how regression tree is better than OLS in terms of heterogeneity. Can anybody help?</p> | g59413 | [
0.005523391533643007,
0.00989468116313219,
-0.010041494853794575,
-0.030053090304136276,
0.009490806609392166,
-0.03471462428569794,
-0.02831326797604561,
-0.008562847040593624,
-0.036046288907527924,
-0.007133951876312494,
0.019420215860009193,
0.0794864296913147,
0.028263745829463005,
0.... |
<p>In SAS's Enterprise Miner there is a "Bucket Transformation" which from what I can tell, is a term that is unique to Enterprise Miner. It takes a continuous variable and groups it to become an ordinal variable with a certain number of bins. I would like to know what it is doing and what this would be called in oth... | g59414 | [
-0.019945716485381126,
0.00042648587259463966,
0.001217060605995357,
-0.07685699313879013,
0.027670366689562798,
-0.06263194978237152,
-0.02544085867702961,
0.0042257667519152164,
-0.068013995885849,
-0.025961581617593765,
0.0011162332957610488,
0.0117282560095191,
0.07874881476163864,
-0.... |
<p>I am writing my master's thesis in quantile multilevel regression.
My professor all of a sudden decided to change the subject of my thesis into something that could be called "quantile multilevel multivariate regression".
He asked me to proof that Manova is a special case of mixed-models (saying that "someone has pu... | g734 | [
-0.01237571518868208,
-0.06155848503112793,
0.00863987673074007,
-0.014403806068003178,
0.025121130049228668,
-0.005993513856083155,
0.02152453549206257,
-0.007234741933643818,
-0.00840030238032341,
0.007740428205579519,
-0.0493379682302475,
-0.010148673318326473,
0.04472731426358223,
0.08... |
<p>Suppose I have a data set that is only left-censored data, ex:</p>
<blockquote>
<p><5, <5, <5, <10, <10, <10</p>
</blockquote>
<p>A technique to handle left-censored data is the Kaplan Meier estimate, see page 5 of this excellent <a href="http://www.public.iastate.edu/~pdixon/stat505/Chapter%20... | g14922 | [
0.01732812263071537,
-0.006994854658842087,
0.006187537685036659,
0.008417446166276932,
-0.0061540803872048855,
-0.026863960549235344,
0.013908651657402515,
0.004214446526020765,
-0.039166949689388275,
-0.01216526236385107,
0.021651972085237503,
0.007368976715952158,
0.04983584210276604,
0... |
<p>I've looked through a lot of literature available online, including this forum without any luck and hoping someone can help a statistical issue I currently face:</p>
<p>I have 5 lists of of ranked data, each containing 10 items ranked from position 1 (best) to position 10 (worst). For sake of context, the 10 items ... | g49809 | [
0.023292189463973045,
-0.03964749723672867,
-0.0265485979616642,
-0.05541164427995682,
0.043716587126255035,
-0.02231895923614502,
0.0438215509057045,
0.008594482205808163,
-0.010943087749183178,
0.015489229001104832,
0.03527156636118889,
-0.015575770288705826,
0.02943018078804016,
-0.0176... |
<p>Let $(x_i,y_i,z_i)_{i=1,\dots,n}$ be an i.i.d. sample of $(X,Y,Z)$. How one can estimate the following object
$$\int_{-\infty}^xf(\bar x,y|z)\mathrm{d}\bar x$$
where $f(x,y|z)$ is a density of $X,Y$ conditional on $Z$.</p>
<p>We know that $F(x) = \int_{-\infty}^xf(\bar x)\mathrm{d}x$ can be estimated using $\hat F... | g14924 | [
-0.057872869074344635,
0.001622951589524746,
-0.028577646240592003,
-0.04817845672369003,
-0.018324296921491623,
-0.0617084801197052,
0.052285972982645035,
0.0018434061203151941,
-0.0290924534201622,
0.005619574338197708,
-0.01592821627855301,
0.031118081882596016,
-0.007414550986140966,
0... |
<p>I am have to make this basic game engine.The offensive player has 5/6 chance to make a shot(83%).. And defense player has 4/6 chance(57.6%) to defend it.So when offensive player make a shot,how do I calculate the success rate of both players.Thank you for taking time to read this.I am starting new in this.Thanks in ... | g14925 | [
-0.013785085640847683,
-0.033173736184835434,
0.0010672028874978423,
0.01616375707089901,
0.013204188086092472,
0.03983790799975395,
0.014243056066334248,
-0.01643889583647251,
-0.05125358700752258,
-0.015762917697429657,
0.044627536088228226,
0.04200958088040352,
0.08134087920188904,
-0.0... |
<p>Please forgive this silly question, I'm fairly new to statistics.</p>
<p>Consider this R code:</p>
<pre><code> a = c(1,2,3,4,3,2,3,4,5,5,6,5,4,3,4,5,6,7,8,7,6,6,5,6,7,10,9)
b = c(10,9,7,6,5,6,7,8,4,6,6,5,4,5,6,5,4,5,6,7,5,4,4,5,4,3,2)
mean((a - mean(a))*(b-mean(b)))
[1] -2.42524
cov(a,b)
[1]... | g14926 | [
0.010778240859508514,
-0.03676233068108559,
-0.0097604189068079,
-0.006892832927405834,
0.06850311160087585,
-0.036182649433612823,
0.047248724848032,
-0.012283757328987122,
-0.06324455142021179,
-0.03773252293467522,
-0.04089486226439476,
0.041635505855083466,
0.01743616722524166,
0.01858... |
<p>This question is about hypothesis testing in the Bayesian framework which I am new to.</p>
<p>Suppose I have two independent Poisson models with parameters $\lambda_1$ and $\lambda_2$ such that $X \sim Pois(\lambda_1)$ and $Y \sim Pois(\lambda_2)$. $n$ observations are drawn from each of the distributions $X$ and $... | g59415 | [
0.03899244964122772,
-0.029214054346084595,
0.002569850068539381,
-0.01963389478623867,
-0.01926504634320736,
0.0010974962497130036,
-0.09815996885299683,
-0.004398414399474859,
-0.047569576650857925,
-0.017362091690301895,
0.02590475231409073,
0.035622719675302505,
0.01868738792836666,
0.... |
<p>I know the general question about bias variance has been asked before. I understand the frequentist approach and the concept of model selection and the impact of bias and variance on "accuracy" of a prediction.
I am looking for an intuitive explanation of bias and variance from a <strong>Bayesian perspective.</stron... | g31489 | [
0.0024539800360798836,
0.0005981345311738551,
-0.015470239333808422,
0.03378903865814209,
0.016813375055789948,
0.024835525080561638,
0.01570180244743824,
0.047805145382881165,
-0.003231118666008115,
-0.028669578954577446,
0.025981243699789047,
0.026705125346779823,
0.04113230109214783,
0.... |
<p>How do I test for a significant difference between the mortality rate of 4 groups (each group with a different n) </p>
<p>group 1: mortality rate = 30.9%, n=55
group 2: mr = 0%, n = 4
group 3: mr = 23.3%, n = 30
group 4: mr = 24.6%, n = 69</p>
<p>is it sufficient to just do a t-test between each group? seems like ... | g14931 | [
-0.016739146783947945,
-0.019209906458854675,
-0.01051553525030613,
-0.034085582941770554,
0.0023224707692861557,
-0.033139560371637344,
-0.00544535368680954,
0.010459251701831818,
-0.04756840690970421,
0.010071507655084133,
0.07705934345722198,
-0.014297564513981342,
0.03138637915253639,
... |
<p>I have data on many trips (same route). The trip content: <code>latitude</code>, <code>longitude</code>, and <code>time at bus stop</code>. I want to detect the trips that are in the same direction (will have to be two clusters: same direction and opposite direction). Is there an algorithm that can do this?</p> | g14932 | [
0.011366899125277996,
-0.01579500176012516,
-0.019056137651205063,
-0.01863153837621212,
0.007291881833225489,
-0.04560622200369835,
-0.008307955227792263,
0.025187939405441284,
-0.04246543347835541,
0.031236719340085983,
0.008993660099804401,
0.04454689100384712,
0.06611495465040207,
0.01... |
<p>I develop an application in which I constantly get samples of heart pulse.</p>
<p>I defined an interval of $t$ seconds.</p>
<p>In each $t$ seconds I have $n$ samples.</p>
<p>In every interval, I want to calculate the tendency of those $n$ samples. For example, lets say I have $n = 5$, and I have samples with valu... | g59416 | [
0.0834578424692154,
-0.043410032987594604,
-0.0019690776243805885,
-0.008288669399917126,
-0.006518749054521322,
-0.006273763254284859,
0.03034077025949955,
-0.003455026540905237,
-0.015812594443559647,
-0.06586778908967972,
0.03719160333275795,
0.03618360310792923,
-0.030365092679858208,
... |
<p>I have a finite set A of discrete values and I have a packet flow (computer networking) where each packet is assigned with a value from A. I want to determine if it is possible to predict the long-term (e.g. after a minute) characteristic (regarding A) of this packet flow by making short-term (e.g. after a few secon... | g13351 | [
0.006388514302670956,
-0.019598959013819695,
-0.01699521765112877,
-0.04135136678814888,
-0.030841946601867676,
-0.01642455719411373,
-0.02474100887775421,
-0.025109687820076942,
-0.028089504688978195,
-0.02500363625586033,
0.003267730353400111,
0.04513834789395332,
0.07896402478218079,
0.... |
<p>I have always thought that, when dealing with multinomial logistic regression, the idea was to linearly model the "logistic" functions of the probability densities of the different response categories (as explained <a href="https://en.wikipedia.org/wiki/Multinomial_logistic_regression#As_a_set_of_independent_binary_... | g14934 | [
-0.020353559404611588,
-0.005647807847708464,
-0.005426258314400911,
-0.02050659991800785,
-0.00012789806351065636,
-0.07262618839740753,
-0.012721014209091663,
-0.0022857000585645437,
-0.03846217691898346,
-0.016523871570825577,
-0.05179908126592636,
-0.028639530763030052,
0.041852615773677... |
<p>I'm working with the <a href="http://cran.r-project.org/web/packages/changepoint/index.html" rel="nofollow">changepoint</a> R package in R and I understand everything but the penalty value. I know it changes the units of change in the mean, but I still don't know how to interpret it. How do I know how significant is... | g59417 | [
-0.0012063670437783003,
0.023734072223305702,
-0.02641337737441063,
-0.05698249489068985,
0.07422119379043579,
-0.04692763462662697,
0.04354855418205261,
0.03873535245656967,
-0.04675678536295891,
0.04685695469379425,
-0.025724604725837708,
0.034181542694568634,
0.055559057742357254,
-0.01... |
<p>How does SAS calculate t-values? </p>
<p>For example, say we have two variables: intercept (which is always present) and temperature in a model that is regressing temperature on mortality in a certain region.</p>
<p>t Value</p>
<p>-1.39 (Intercept)</p>
<pre><code>(B) (Temperature)
</code></pre>
<p>How might o... | g14935 | [
0.04062337800860405,
-0.038806963711977005,
-0.018031872808933258,
-0.043052200227975845,
0.019671788439154625,
-0.044079165905714035,
0.029634414240717888,
0.0360705740749836,
-0.07830394059419632,
-0.03902590274810791,
-0.03598838299512863,
0.058569248765707016,
0.06510377675294876,
0.00... |
<p>It is said that $S_{xx} = \sum_{i=1}^n(x_i−\overline x)^2 = \sum_{i=1}^n x_i^2 −n\overline x^2$. </p>
<p>I suspect this is simple algebra but I am missing something still. How does this work? </p>
<p>Further, Wikipedia mentions that the MSE is $\sum_i \frac{(X_i - \overline X)^2}{n-2}$. However, my text notes ... | g59418 | [
-0.029655897989869118,
0.035079602152109146,
-0.015445326454937458,
0.012695781886577606,
-0.05014485493302345,
-0.022121863439679146,
0.028409814462065697,
-0.006975964643061161,
-0.020268334075808525,
-0.0253767017275095,
-0.07429371029138565,
0.059936728328466415,
0.04624813050031662,
-... |
<p>I have a data set that is a group of participants who accept or reject each of two devices, and I'd like to test if the two devices are accepted at different rates. Summary table like so</p>
<pre><code>Overall Acceptance
Accept Reject
X 124 20
Y 111 33
</code></pre>
<p>What's the best ... | g59419 | [
-0.006058520637452602,
0.07849571108818054,
0.016998013481497765,
-0.05161186680197716,
-0.031471896916627884,
-0.04539792612195015,
0.05872548744082451,
0.031071661040186882,
-0.04341347515583038,
-0.010877265594899654,
0.03933688625693321,
0.04871378466486931,
-0.005601477809250355,
0.01... |
<p>My (basic) understanding of a 95% confidence interval is that it is the interval within which the sample mean would fall 95 times should you take 100 random samples from the population.</p>
<p>My query is this, I often see confidence intervals being used in situations that I would call descriptive, rather than infe... | g14936 | [
0.009131494909524918,
-0.004427536390721798,
-0.013227562420070171,
0.001901555573567748,
-0.034141216427087784,
0.027517376467585564,
0.030512550845742226,
-0.01720687933266163,
-0.030920596793293953,
-0.03874463960528374,
0.02346535585820675,
0.014123436063528061,
0.0749025046825409,
-0.... |
<p>My dependent variable is corruption. I want to test the effect of press freedom and democracy on corruption. The measure for press freedom varies from 1-100 and the democracy variable is ordinal scaled from 1-7. Can I make an interaction term between press freedom and democracy?</p> | g59420 | [
-0.0013635269133374095,
0.0031022110488265753,
-0.02181801199913025,
-0.06025530397891998,
-0.0018402284476906061,
-0.023244261741638184,
-0.018549177795648575,
-0.01609315164387226,
-0.0009147056262008846,
0.026357857510447502,
0.01766972243785858,
0.012732277624309063,
-0.01324117835611105... |
<p>When characterizing an information measure one desires to have the following 'Grouping' property (cf., Cover&Thomas, Ch.2 exercise 46) </p>
<p>$$H(p_1, p_2,\dots, p_n)=H(p_1+p_2, p_3,\dots, p_n)+(p_1+p_2)H(\frac{p_1}{p_1+p_2},\frac{p_2}{p_1+p_2})$$ </p>
<p>(a.k.a. recursive). An analogous Grouping axiom is emp... | g59421 | [
-0.05342778563499451,
-0.0046416218392550945,
-0.034562379121780396,
-0.01664447970688343,
0.0176379457116127,
-0.007324391510337591,
0.00827487837523222,
0.02105559967458248,
-0.0351414829492569,
0.010555652901530266,
-0.016165249049663544,
0.007860851474106312,
-0.035354163497686386,
0.0... |
<p>The Pearson's coefficient between two variables is quite high (r=.65). But when I rank the variable values and run a Spearman's correlation, the cofficient value is much lower (r=.30). </p>
<ul>
<li>What is the interpretation of this?</li>
</ul> | g44184 | [
0.04350696876645088,
-0.042355287820100784,
-0.01938539184629917,
-0.09119590371847153,
0.04949873313307762,
0.02397092804312706,
0.03363491967320442,
0.021470189094543457,
-0.017536981031298637,
-0.013930853456258774,
-0.01253620907664299,
0.044174764305353165,
-0.005392164457589388,
-0.0... |
<p>I would like simulate appearance of publications in a forum and I need know what is the probability distribution of new question being asked in a forum. In my first simulation I used to normal distribution, but I think that the best distribution can be exponential distribution.</p> | g59422 | [
0.030828699469566345,
0.06546096503734589,
-0.0036351592279970646,
-0.0628940612077713,
0.014793477952480316,
0.00257406709715724,
0.019971059635281563,
-0.0021113059483468533,
-0.026072552427649498,
-0.01169898733496666,
0.05795127898454666,
0.009729713201522827,
-0.0031860554590821266,
0... |
<p>I have a random variable denoted $N$.
Then I have random variables denoted $X_1$, $X_2$, ..., $X_N$ distributed according to a uniform distribution. I have also random variables denoted $Y_1$, $Y_2$, ..., $Y_N$ distributed according to this same probability distribution.</p>
<p>If we consider the variable $S_X$ suc... | g59423 | [
-0.0021535465493798256,
0.012333158403635025,
-0.00646029831841588,
0.005449870601296425,
-0.027246786281466484,
-0.013805347494781017,
-0.05325782671570778,
-0.008815150707960129,
0.022665133699774742,
0.045939553529024124,
-0.053168654441833496,
0.011900307610630989,
-0.05376449599862099,
... |
<p>I am wondering if anyone knows of a way to run a multiple mediation model in R. I know the <a href="http://cran.r-project.org/web/packages/mediation/index.html" rel="nofollow">mediation</a> package allows for multiple simple mediation models, but I want to run one model that evaluates multiple mediation models simul... | g59424 | [
0.001607001875527203,
-0.04087873175740242,
0.014240840449929237,
-0.036243028938770294,
0.038005340844392776,
-0.07137642055749893,
0.03265880048274994,
0.05841532722115517,
-0.02504013665020466,
-0.04024882614612579,
0.000029438584533636458,
-0.05312570929527283,
0.0666353851556778,
0.05... |
<p>I have a multiple linear regression model, and need to test the significance of the slopes. My professor says that there are two ways to go about it - so which should I use? The questions in the exam would have the standard error of the regressors along with the estimated value of the regressors as well.</p> | g59425 | [
0.0700366422533989,
-0.048581480979919434,
0.002379220211878419,
0.02736140415072441,
0.06048823520541191,
0.005609947256743908,
0.025492537766695023,
0.02589612454175949,
-0.021404005587100983,
-0.02206873521208763,
-0.006891048047691584,
0.004509577061980963,
0.06062856689095497,
0.02213... |
<p>I'm trying to figure out why certain methods are used for comparing models in Bayesian statistics. DIC is often used in Bayesian model comparison. However, I'm under the impression that one could calculate likelihood and/or BIC, too. </p>
<p>Specifically, I've been told that the calculation of likelihood could depe... | g59426 | [
0.031175315380096436,
-0.04161154851317406,
-0.0030092194210737944,
-0.021397609263658524,
0.029618877917528152,
-0.0011767192045226693,
0.052653469145298004,
0.05067216232419014,
-0.05821969732642174,
-0.05910269543528557,
0.01256667822599411,
0.0022084086667746305,
0.08182894438505173,
0... |
<p>I conducted an experiment in a factorial design: I measured light (PAR) in three herbivore treatments as well as six nutrient treatments. The experiment was blocked.</p>
<p>I've run the linear model as follows (you can download the data from my website to replicate)</p>
<pre><code>dat <- read.csv('http://www.na... | g59427 | [
-0.024949409067630768,
-0.049596820026636124,
-0.020490800961852074,
0.012303720228374004,
0.016446644440293312,
-0.022502068430185318,
0.053347595036029816,
-0.01022238191217184,
-0.04496268182992935,
0.012607070617377758,
-0.019378220662474632,
0.06104448437690735,
0.03287167847156525,
0... |
<p>We are often confronted with brand attribute associations (Yes/No) in Market Research, and more often than not we need to do Factor Analysis (we use PCA under Factor in SPSS) in order to reduce the data to something useful and interpretable. </p>
<p>What is the best method of data reduction when you have binary dat... | g44191 | [
-0.013088990934193134,
-0.0059127602726221085,
0.01728958450257778,
-0.05506265163421631,
-0.03168268874287605,
-0.02738868072628975,
0.03151027858257294,
0.041026826947927475,
0.0002506727469153702,
-0.01687275432050228,
0.0558558814227581,
0.011116121895611286,
0.017495904117822647,
0.04... |
<p>How Breusch-Pagan can't reject the null for a series like that?</p>
<pre><code>> x = c(rnorm(10), rnorm(100,sd=10), rnorm(100,sd=25))
> mod = lm(x[-1]^2~x[-210]^2)
> plot(mod$res,type='l')
> bptest(mod)
studentized Breusch-Pagan test
data: mod
BP = 1.1085, df = 1, p-value = 0.2924
</code></p... | g44192 | [
-0.01649361476302147,
0.020461786538362503,
-0.0032223646994680166,
-0.06818440556526184,
0.0032693336252123117,
0.0042914473451673985,
0.024148307740688324,
-0.0011495370417833328,
-0.0175344105809927,
-0.06148079037666321,
-0.029005689546465874,
0.10518185049295425,
0.03828659653663635,
... |
<p>Let's say we are interested in approximating the following expectation:</p>
<p>$$\mathbb{E}[h(x)] = \int h(x)\pi(x) dx$$</p>
<p>Where $h(x)$ is an arbitrary function and $\pi(x)$ is a distribution known only up to a normalizing constant. We could approximate this expectation using a Metropolis-Hastings sampler to... | g59428 | [
0.011896271258592606,
-0.030653158202767372,
0.000586364883929491,
-0.05420743301510811,
-0.05734386667609215,
-0.012667522765696049,
-0.012744727544486523,
0.013290843926370144,
-0.054725077003240585,
0.04686910659074783,
0.018616337329149246,
0.08279009908437729,
0.033478979021310806,
0.... |
<p>Is there any R package to implement relaxed lasso for Cox's proportional hazards model? Thank you.</p> | g14948 | [
0.0533326156437397,
-0.052491579204797745,
0.019516166299581528,
0.01442796178162098,
0.015697870403528214,
-0.015987800434231758,
-0.027539577335119247,
0.003728783456608653,
-0.042237333953380585,
-0.02130044437944889,
-0.003441073000431061,
0.010167266242206097,
0.08630190044641495,
-0.... |
<p>Sorry to ask a stupid question, but I have problems using the package segmented.</p>
<p>My linear regression is very simple, between offer and demand:</p>
<blockquote>
<p>linearModel <- lm(demand~offer)</p>
</blockquote>
<p>And so should be my model using "segmented":</p>
<blockquote>
<p>piecewiseModel &l... | g59429 | [
0.01791258342564106,
-0.03352799266576767,
-0.016408860683441162,
-0.05180857330560684,
0.00797291286289692,
-0.0036765667609870434,
-0.027066275477409363,
0.013283543288707733,
-0.048652201890945435,
-0.0132144121453166,
-0.003673143917694688,
-0.004197204019874334,
0.018825190141797066,
... |
<p>Working with the generalized covariance formula for vector, $x$, I have: $E[(x-\mu)(x-\mu)^T)] = E(xx^t) - \mu E(x^T)$</p>
<p>But the term $E(x^T)$ doesn't make much sense to me. Does anyone have an idea why I'm getting this term with my matrix algebra?</p> | g59430 | [
-0.016508987173438072,
0.025751318782567978,
0.02005642093718052,
-0.015477204695343971,
0.005669400095939636,
0.018450172618031502,
0.017408272251486778,
0.033013612031936646,
-0.026316586881875992,
0.053236331790685654,
0.006373865995556116,
0.03790760412812233,
0.032266244292259216,
-0.... |
<p>I have a table of customer details with demographic information and a "total customer time" that indicates how long the customer has been a customer. I need to be able to query this table in an ad-hoc way, for instance I might ask, "what is the average total customer time for all customers in Florida and with an inc... | g44194 | [
0.007583319675177336,
0.04329562187194824,
-0.031921714544296265,
-0.057333189994096756,
-0.04242323711514473,
-0.10075291246175766,
0.025735462084412575,
0.01805625483393669,
-0.052228473126888275,
0.017162133008241653,
0.035647470504045486,
0.0408342145383358,
0.020776668563485146,
0.017... |
<p>The Gelman and Rubin diagnostic is used to check the convergence of multiple mcmc chains run in parallel. It compares the within-chain variance to the between-chain variance, the exposition is below:</p>
<p><strong>Steps (for each parameter):</strong></p>
<ol>
<li>Run m ≥ 2 chains of length 2n from overdispersed s... | g36172 | [
0.042519133538007736,
-0.006652723532170057,
-0.0016396878054365516,
-0.04764815792441368,
0.004170005675405264,
-0.03454691916704178,
0.012928836047649384,
0.02329113520681858,
-0.04724365845322609,
-0.008422142826020718,
0.011695140041410923,
0.03620307520031929,
-0.03216762840747833,
0.... |
<p>What is the basic argument upon which ridge and lasso regression are based on? I went through <a href="http://en.wikipedia.org/wiki/Tikhonov_regularization" rel="nofollow">Tikhonov regularization wiki</a> where it was mentioned that </p>
<blockquote>
<p>In many cases, tikhonov matrix is chosen as the identity ma... | g14951 | [
0.0681479200720787,
-0.01558145321905613,
-0.007651515770703554,
0.028103452175855637,
0.07065635174512863,
-0.05871354788541794,
0.05374303460121155,
0.036124639213085175,
0.0028106174431741238,
-0.007103279232978821,
-0.012890152633190155,
0.054794736206531525,
0.0474751740694046,
0.0498... |
<p>I have an <code>ARIMA(0,2,1)</code> model. How do i estimate the $\hat{e}_t$ component of the model. I have read a whole lot of theories that confuses me the more. Is there any practical way of estimating this $\hat{e}_t$? Does <code>R</code> offer any help to that too?</p>
<p>I know that my <code>ARIMA(0,2,1)</cod... | g59431 | [
-0.008161894045770168,
-0.049651507288217545,
-0.0021550317760556936,
0.0010753701208159328,
0.03410317748785019,
-0.035674382001161575,
0.044824302196502686,
0.02742086909711361,
-0.040163468569517136,
0.03980478644371033,
-0.005696261767297983,
0.05254851281642914,
0.07278939336538315,
0... |
<p>Has anyone any idea how one could distinguish time series according to certain properties?
The only time series properties I know are stationarity/nonstationarity and homoskedasticity/heteroskedasticity. But are there any other possibilities to distinguish time series?</p> | g12324 | [
0.00435999920591712,
-0.01457155030220747,
0.004334531258791685,
0.023241527378559113,
0.013631617650389671,
-0.026573847979307175,
0.003707334166392684,
-0.02629459649324417,
-0.017698295414447784,
0.022350404411554337,
0.014911158010363579,
0.014658153057098389,
0.04715001583099365,
0.03... |
<p>I have this mixture of a shifted binomial and discrete uniform:
$$
P(R=r)=\left\{
\pi\binom{m-1}{r-1} (1-\xi)^{r-1}\xi^{m-r}+(1-\pi){1\over m}\right\}
$$
Having fixed $\xi$, $\pi$, $m$ to be specific values, how can I generate N values for the random variable $R$? Let's say for example N = 100, 300 and 900.</p> | g14954 | [
-0.040423087775707245,
-0.009858321398496628,
-0.020470980554819107,
-0.03773820400238037,
-0.0020662646275013685,
-0.026332885026931763,
-0.020660193637013435,
0.025845516473054886,
0.009383118711411953,
-0.03186380863189697,
-0.03931121528148651,
-0.0013434166321530938,
0.01218015607446432... |
<p>I have read that leave-one-out cross-validation provides a relatively <em>“unbiased estimate of the true generalization performance”</em> (e.g. <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CC8QFjAA&url=http://jmlr.org/papers/volume11/cawley10a/... | g14955 | [
0.038768235594034195,
-0.000648770947009325,
-0.0014785961247980595,
-0.018676379695534706,
0.009990138001739979,
0.015998804941773415,
0.08842107653617859,
0.017624936997890472,
0.00027504301397129893,
0.03228913992643356,
-0.012787781655788422,
-0.007296152878552675,
-0.023613497614860535,... |
<p>I'm analyzing risk to drivers, i.e. driver deaths/distance driven.</p>
<p>Over time distance driven increases (people drive more) while ceteris paribus driver deaths decline (vehicles are safer.)</p>
<p>To deal with these unstable variances, should I define risk as</p>
<pre><code>log(deaths/distance)
</code></pre... | g25187 | [
0.028194496408104897,
0.01970665529370308,
-0.03626302629709244,
-0.011242486536502838,
0.02486300840973854,
0.0038692301604896784,
0.011967764236032963,
0.0016608935547992587,
-0.05767130106687546,
-0.0604776069521904,
-0.01724587008357048,
-0.004535455722361803,
0.04631457477807999,
-0.0... |
<h2>Determining Binomial Condition Probability of a Random Sample</h2>
<p>I have a question about binomial probability involving a conditional event. This problem keeps tripping me up, because while I know how to calculate the binomial probability that a random variable is a failure, i don't know how to calculate the ... | g33748 | [
0.001109371893107891,
-0.020758910104632378,
0.004862440284341574,
-0.000579596555326134,
-0.02972990833222866,
-0.0034121328499168158,
0.02230072394013405,
0.059492744505405426,
-0.03450927883386612,
-0.05051516368985176,
0.005339906085282564,
0.024158112704753876,
0.03162252902984619,
-0... |
<p>What variable selection approach should I consider if I have thousands of predictors with clusters that are extremely correlated? </p>
<p>For example I might have a predictor set $X:= \{A_1,A_2,A_3,A_4,...,A_{39},B_1,B_2,...,B_{44},C_1,C_2,...\}$ with cardinality $|X| > 2000$. Consider the case where all $\rho(A... | g33749 | [
0.04403085634112358,
-0.058631781488657,
0.010597028769552708,
-0.011546415276825428,
-0.018801329657435417,
-0.03502696380019188,
0.034907564520835876,
0.0187765434384346,
0.025358691811561584,
-0.0017646143678575754,
0.03755020722746849,
0.03647714480757713,
0.05012311413884163,
-0.00270... |
<p>How do I specify for a variable to be uniformly sampled from the discrete values $1,2,\ldots,10$ in JAGS? I guess I want to use the dcat() distribution, but I have yet to find good documentation of the parameters for this.</p> | g59432 | [
0.027035923674702644,
-0.04130661487579346,
-0.027319053187966347,
-0.1264963299036026,
-0.01797829382121563,
-0.04513892903923988,
-0.02707071229815483,
0.006291152909398079,
-0.0505620576441288,
-0.030594199895858765,
-0.03279343247413635,
-0.018444202840328217,
0.0726032629609108,
0.009... |
<p>I am having trouble trying to figure out how to report categorical and continuous data in one table. I want to create a descriptive table summarizing some of the categorical and continuous data from the 3 treatment groups I had.</p> | g59433 | [
-0.014128570444881916,
-0.0015736387576907873,
-0.03532497584819794,
-0.05062737315893173,
-0.01149747334420681,
-0.01596236601471901,
0.0015714558539912105,
0.05206131562590599,
-0.03610696643590927,
-0.015331465750932693,
0.01574004627764225,
-0.0006899465806782246,
0.055101361125707626,
... |
<p>I need to analyse objective crime data (indexed) with a time series intervention analysis. However, I have only yearly index from 2003 to 2011. I also have subjective crime data and would like to see if there is a relation between the two different data over time.
What analysis would you advise?</p>
<p>Also, what d... | g59434 | [
0.033487580716609955,
-0.008463343605399132,
0.0020193669479340315,
-0.04232358932495117,
-0.0014735792065039277,
-0.03672067075967789,
0.05994848161935806,
0.023206662386655807,
-0.02078448235988617,
0.016486534848809242,
0.04845517873764038,
0.025450991466641426,
-0.006282726768404245,
-... |
<p>My predictions coming from a logistic regression model (glm in R) are not bounded between 0 and 1 like I would expected. My understanding of logistic regression is that your input and model parameters are combined linearly and the response is transformed into a probability using the logit link function. Since the lo... | g59435 | [
0.011545304208993912,
0.0033574416302144527,
-0.0023388757836073637,
0.012080113403499126,
0.0162854865193367,
-0.01423395425081253,
0.027222365140914917,
0.004532793071120977,
-0.04290691390633583,
-0.06068393215537071,
0.04230000823736191,
0.02397068403661251,
0.0202686358243227,
-0.0216... |
<p>I came across the scale parameter used in the logit and probit models. Does any one know what that is and what it is used for? What would go wrong if I did not use it?</p> | g59436 | [
-0.009109235368669033,
0.04620814323425293,
-0.01000616978853941,
-0.08607155084609985,
0.06147697567939758,
0.08074884116649628,
-0.04594246670603752,
-0.04677757993340492,
-0.05884157121181488,
0.004482848569750786,
-0.008887100033462048,
-0.03350627422332764,
0.05339014157652855,
-0.017... |
<p>I am reading a research report. In that report, they used some elementary statistical methods to analyze their data. There is one quantity they computed called the contribution (of a factor), but they have not provided the definition for that. I am confused. I never heard of the contribution of a factor. It seems th... | g14961 | [
0.04298052191734314,
-0.007177780847996473,
0.004486199468374252,
-0.03440611809492111,
0.050283461809158325,
-0.019169986248016357,
0.04809800907969475,
0.043022289872169495,
0.017481261864304543,
-0.06790850311517715,
-0.022709453478455544,
0.014904050156474113,
0.07435231655836105,
-0.0... |
<p>I am doing a study of the relationship between two items say A and B. The data consists of information printed on the annual reports from say 2000 - 2010 (10 years). For each item, i.e. A and B there are sub variables. Item A has 3 variables with 9 indicators and item B has 1 variable with 2 indicators.</p>
<p>The ... | g14962 | [
0.04258478060364723,
-0.07577783614397049,
-0.02226979099214077,
-0.03053310327231884,
-0.048316605389118195,
-0.004285711329430342,
-0.03963044658303261,
0.014632456935942173,
0.008196450769901276,
-0.03959580510854721,
0.03977608308196068,
-0.0087253013625741,
0.020372802391648293,
-0.00... |
<p>I am using Matlab, I have a $600 \times 9$ matrix with each row representing the 9 features which I am trying to evaluate using logistic regression.</p>
<ol>
<li><p>I understand that I need to perform feature scaling, but do I need to perform it on both the training and the testing set as well?</p></li>
<li><p>I ha... | g59437 | [
0.03425281494855881,
0.007767609786242247,
-0.004326149821281433,
-0.03481220081448555,
0.06165292486548424,
-0.07061310112476349,
0.020058156922459602,
0.05352037400007248,
-0.01797836646437645,
-0.03244934603571892,
-0.042062222957611084,
0.04236791282892227,
0.020361319184303284,
-0.011... |
<p>I am reading the books about linear regression. There are some sentences about the L1 and L2 norm. I know them, just don't understand why L1 norm for sparse models. Can someone use give a simple explanation?</p>
<p>Thanks</p> | g59438 | [
-0.01238502562046051,
-0.03917894512414932,
-0.0008593713282607496,
0.014417563565075397,
0.011698867194354534,
-0.024497151374816895,
0.030255591496825218,
0.0739227831363678,
-0.048367977142333984,
-0.002889991970732808,
-0.010006268508732319,
0.011061792261898518,
0.01787165179848671,
0... |
<p>I have multiple variables (here: weight, horizontal diameter, price and dummy) related to different factors (here: Apple, Orange, Banana and Avocado):</p>
<pre><code>Fruit Weight HorDiam Price Dummy
Apple 60 60 5 4
Apple 50 70 8 6
Orange 80 75 7 ... | g14966 | [
-0.01138902734965086,
-0.014662832021713257,
0.0058359671384096146,
-0.05379101634025574,
-0.010036259889602661,
-0.004803918302059174,
0.01682712882757187,
-0.030433349311351776,
-0.06974466145038605,
0.02072102390229702,
0.028353959321975708,
0.014815686270594597,
0.048829786479473114,
-... |
<p>Suppose you throw 1000 darts where each dart has 0.5 probability of scoring. For the first 500 darts each is worth 1 point, for the second 500 darts each is worth 3 points. If you score 1500 points, how many 3 point darts have you scored most likely?</p>
<p>If I use the likelihood method, I need to maximize the fol... | g59439 | [
-0.013315165415406227,
-0.023316269740462303,
0.014737413264811039,
0.04617532342672348,
0.030084632337093353,
-0.021261507645249367,
-0.006926277186721563,
0.0059167067520320415,
0.006005091592669487,
0.044810499995946884,
-0.02263585664331913,
0.013438304886221886,
0.04523928090929985,
-... |
<p>I am quite new with probit models and I recently asked some questions about one of model. I was wondering of one of you could help in interpreting those results.</p>
<p>FYI all dependent variables are logged and heteroskedasticity was taken care of using robust standard errors.
I then used the "margins, dydx(*)" co... | g59440 | [
-0.028461646288633347,
-0.02942640706896782,
-0.017956528812646866,
-0.03104504570364952,
0.04070361331105232,
0.026344059035182,
0.023464826866984367,
0.022936515510082245,
-0.04452785849571228,
-0.05901011452078819,
0.03137405216693878,
0.04063171148300171,
0.024021679535508156,
-0.00156... |
<p>My question is pretty simple.</p>
<p>Descriptive statistics, like mean, median, sd, etc... for time series data with just 9 points are computed in same way as for uncorrelated data?</p>
<p>Or the mathematics is totally different?</p>
<p>Thanks</p> | g59441 | [
0.08217441290616989,
0.01629737764596939,
-0.00793434027582407,
-0.03120426833629608,
-0.014570039696991444,
-0.014112243428826332,
0.0026839207857847214,
-0.02427053637802601,
-0.014444779604673386,
-0.0731496810913086,
0.05198437348008156,
0.014508304186165333,
0.07994629442691803,
-0.04... |
<p>I am preparing a presentation on Survival Analysis models, with specific focus on the Cox model. I have been using such model (including its competing risks generalization) for some time now, but I still cannot find an easy way to think about the error term of the model, $\varepsilon$.</p>
<p>Suppose I am in the si... | g59442 | [
0.045654233545064926,
-0.03709132596850395,
-0.005162620451301336,
0.006795091088861227,
0.07796052098274231,
-0.002027627546340227,
0.012361721135675907,
0.004135219380259514,
-0.032547879964113235,
0.01602907106280327,
-0.010456676594913006,
0.014154486358165741,
0.1064624935388565,
-0.0... |
<p>I have a problem that has puzzled me for a long time. It involves linear models and spline functions. I need to model "time since diagnosis" when some individuals never had a diagnosis. I use Poisson model where I have split time on age and time since diagnosis. The data set may look like this (with millions upon mi... | g469 | [
-0.0008909328025765717,
-0.04425531625747681,
-0.01679692231118679,
-0.03760908171534538,
0.005136570893228054,
-0.0327911339700222,
-0.009446647018194199,
0.013625279068946838,
-0.03363557532429695,
-0.037281349301338196,
-0.023739632219076157,
0.015110732987523079,
0.026736723259091377,
... |
<p>Assume I have random variables $X$ and $Y$. $X$ is observable; $Y$ is not. We also know that, if $X \leq Y$, $Z = f(X,Y)$ where $Z$ is a third random variable and $f(\cdot)$ is a known function; otherwise $Z$ is missing. $Z$ is also observable (missing or a real number).</p>
<p>Assume I know the distribution of $X$... | g14971 | [
-0.022197231650352478,
-0.037572164088487625,
-0.016269361600279808,
0.021000228822231293,
0.004993872717022896,
0.01185523346066475,
-0.010640917345881462,
-0.022672608494758606,
-0.015791526064276695,
0.01623290590941906,
-0.025465045124292374,
0.009489827789366245,
0.039069920778274536,
... |
<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/6920/efficient-online-linear-regression">Efficient online linear regression</a> </p>
</blockquote>
<p>Is there a summation representation for multivariate regressions?</p>
<p>For example, if I regress $y$... | g49555 | [
-0.01100009586662054,
-0.015126957558095455,
-0.022132400423288345,
-0.03947371989488602,
-0.012871441431343555,
-0.09704334288835526,
0.09394647926092148,
-0.00995430164039135,
-0.061599284410476685,
0.017799057066440582,
-0.0424095056951046,
0.02707267738878727,
0.02164684422314167,
0.03... |
<p>Can you still used the least significant difference test even if the F test is not significant?</p> | g59443 | [
-0.009563342668116093,
-0.013241252861917019,
0.018421432003378868,
0.019262198358774185,
-0.006711937021464109,
-0.004704668186604977,
-0.01995825208723545,
0.019397560507059097,
0.010024502873420715,
-0.06072581931948662,
0.05465501546859741,
-0.01420113630592823,
-0.010447333566844463,
... |
<p>I would like to find out how quickly etymological (history of words) knowledge becomes obsolete. I thought I could compare several editions of one dictionary published over a long period of time. My problem is that the size of this dictionary has grown during this period from four to twelve thousand words, and I do ... | g14974 | [
0.01789146102964878,
0.04092235490679741,
-0.013024983927607536,
-0.07791690528392792,
-0.02846691757440567,
-0.046153999865055084,
-0.011894993484020233,
0.07253345847129822,
-0.005732050631195307,
0.08911646902561188,
-0.02051222324371338,
-0.04224509000778198,
0.06345295161008835,
0.041... |
<p>I am wondering if someone could point me to the direction of support vector machines being used for longitude latitude. It seems logical that the possible complexity in SVM would be great for modelling variables dependent of location.</p>
<p>In this case, I am trying to model depression dependent on US zip codes. M... | g59444 | [
0.03165930137038231,
0.005921657662838697,
0.008634285070002079,
-0.0276828370988369,
-0.03848452866077423,
-0.000747536716517061,
-0.0017797724576666951,
0.08143378794193268,
-0.030777376145124435,
0.005060059484094381,
0.05765663832426071,
-0.01954750344157219,
0.06570009887218475,
-0.00... |
<p>I need help in defining the type of distribution used in software so that I could use some standard distribution library for this purpose. I apologize for not using proper terms. It takes "center" value and an alpha parameter (0 to 1) and produces N values within a given range, so that values are "clustered" around ... | g59445 | [
0.0521930493414402,
-0.030997084453701973,
-0.03549420088529587,
-0.04955069720745087,
0.011127476580440998,
-0.028113707900047302,
0.030381737276911736,
-0.013883926905691624,
-0.04236198216676712,
-0.061634551733732224,
-0.012220272794365883,
-0.01444168109446764,
0.024661194533109665,
0... |
<p>I am comparing two different populations (with different sizes) of models, for each individual I have a score. I'd like to compare not only the difference of the two means but the maximum value. I've learnt in the past to perform significance test when comparing averages between groups but this is the first time tha... | g59446 | [
-0.05762702599167824,
-0.019234666600823402,
-0.0076482961885631084,
-0.0029648791532963514,
0.03225135803222656,
-0.018429800868034363,
-0.043296750634908676,
0.04283589869737625,
-0.029127828776836395,
0.016963571310043335,
-0.0020562417339533567,
0.014574666507542133,
0.03973996266722679,... |
<p>At <a href="http://homepages.gold.ac.uk/aphome/spheric.html#6" rel="nofollow">this website</a> it is stated that "If compound symmetry is met then sphericity is also met."</p>
<p>Is it impossible to construct a data set that has perfect compound symmetry but not perfect sphericity? Why/why not? It's not intuitively... | g59447 | [
-0.008225412108004093,
0.008007867261767387,
-0.004794578067958355,
-0.033990029245615005,
-0.00029661759617738426,
-0.019043471664190292,
0.04486917704343796,
0.0012880750000476837,
-0.05056679993867874,
0.004393474198877811,
-0.02166616916656494,
-0.0450894720852375,
0.015709368512034416,
... |
<p>I am trying to compare the performance of a short and long form of a questionnaire. The long form has 25 items and the short form has 8 of the 25 items. Can DeLong's Test be used to compare the ROC curves? If not which test is most suitable for this analysis?</p> | g59448 | [
0.05386734381318092,
-0.04554300382733345,
-0.006744416430592537,
-0.08038298785686493,
-0.002661580452695489,
-0.04994819685816765,
0.003884875914081931,
-0.0480077862739563,
0.00724954716861248,
-0.040541872382164,
0.006173867732286453,
-0.005266806576400995,
0.0033011052291840315,
-0.04... |
<p>My logistic regression model seems to identify successes very well (about 85% - 94%), but fails to identify the failures (only identifying 18% - 32% correctly). </p>
<p>I have thought of weighting the success and failures differently, but I am not sure of how to do this R. I have tried:</p>
<pre><code>Fr <- ife... | g59449 | [
0.0014467492001131177,
-0.04856358841061592,
-0.022582489997148514,
0.014293259009718895,
0.04484051838517189,
-0.07402671873569489,
0.03132053092122078,
-0.023283256217837334,
-0.07991524785757065,
-0.045921240001916885,
0.006212704349309206,
0.030381783843040466,
0.10021192580461502,
-0.... |
<p>I'm trying to uncover the transition parameters of data of a hidden Markov Model using MATLAB. Using the built in hmmtrain function, I can estimate the parameters quite well (I already know what they are supposed to be as it's simulated data for now), but they are always off by a little. So what I want to do is cons... | g59450 | [
0.014861012808978558,
-0.0016727718757465482,
0.02520465850830078,
0.045262884348630905,
-0.02207530289888382,
-0.029149800539016724,
-0.00839491467922926,
0.046767063438892365,
-0.07606842368841171,
-0.009389057755470276,
-0.03985416144132614,
0.00806061364710331,
0.07787394523620605,
-0.... |
<p>My honours thesis is due in soon and I still haven't thought of a great title. I want something that's clever (perhaps using a pun or two), but also gives insight into what I'm doing. Preferably in the form of "Thesis: A Brilliant Thesis" Everyone loves colons.</p>
<p>So what is my thesis about?</p>
<p>It is a sta... | g14979 | [
0.060972750186920166,
0.06456317007541656,
0.010389148257672787,
-0.053410761058330536,
0.040630731731653214,
0.02030930668115616,
-0.012529497034847736,
-0.044938474893569946,
0.0015595703152939677,
0.012824518606066704,
0.04317086189985275,
0.05622722953557968,
0.11435855180025101,
-0.06... |
<p>I have N binary classifier algoritmhs trained on same single train set and tested on single test set.</p>
<p>1) Which statistical test is appropriate for calculating their statistical difference?</p>
<p>2) Using McNemmar's test with pairwise manner is a valid option?</p>
<ul>
<li>I know ANOVA, which works on K tr... | g14981 | [
-0.01482259202748537,
-0.003677123924717307,
0.017636818811297417,
0.03573983907699585,
0.0008801186922937632,
-0.02890148013830185,
0.00708762789145112,
0.044239968061447144,
-0.04107363894581795,
-0.020323749631643295,
0.013520650565624237,
0.03931686654686928,
0.017731783911585808,
0.04... |
<p>I am using JMP.<br>
If I choose to add higher order terms in the regression model, do I also need to include its main effect (yes or no) and why?</p> | g49556 | [
0.0331263542175293,
-0.03546495735645294,
0.018729818984866142,
-0.022293945774435997,
0.022709675133228302,
-0.018537450581789017,
-0.00864043552428484,
0.04404318705201149,
-0.026385026052594185,
-0.04302041232585907,
-0.047717705368995667,
0.04695780575275421,
-0.00581629853695631,
0.03... |
<p>In a multiclass classification problem, I want to measure the significance of my classifier against the null hypothesis (in this case, chance level). </p>
<p>In <a href="http://www.princeton.edu/~fpereira/Presentations/ipam2008.pdf" rel="nofollow">this paper</a>, in section 3.4, for a binary classifier, it is propo... | g14982 | [
-0.02963513880968094,
0.021797845140099525,
-0.01010509580373764,
-0.037991076707839966,
0.04899389669299126,
-0.05390934646129608,
-0.011984940618276596,
0.06904477626085281,
-0.004151679575443268,
-0.014827693812549114,
-0.0032555474899709225,
0.013813820667564869,
0.028532598167657852,
... |
<p>When trying to fit a AR(p) model to a time series in R, it seems that both ar.ols() and arima() will work. Is there some consideration of when to use which then?</p>
<p>ar.ols() seems to use least square estimation, while arima() uses maximum likelihood or minimize conditional sum-of-squares (default method).</p>
... | g59451 | [
0.05603606998920441,
-0.06300210952758789,
0.0016455642180517316,
-0.035322342067956924,
-0.008018922992050648,
-0.015237380750477314,
0.01033843494951725,
0.008249533362686634,
0.0012902931775897741,
0.027341805398464203,
0.04767174273729324,
0.01105344109237194,
0.10241881757974625,
-0.0... |
<p>I recently came across a paper that uses the McNemar test to evaluate the effectiveness of an intervention to improve adherence to treatment. The study used a pre/post test design whereby the adherence behaviour for both the control and intervention group was measured using the same instrument and expressed as conti... | g14986 | [
-0.02553444355726242,
-0.05687830224633217,
0.015193399041891098,
-0.035269174724817276,
-0.06255175173282623,
-0.056336384266614914,
0.04407220706343651,
0.028310708701610565,
-0.031124593690037727,
0.002800497692078352,
0.055032990872859955,
-0.010502140037715435,
0.0035742816980928183,
... |
<p>It is easy to find a package calculating area under ROC, but is there a package that calculates the area under precision-recall curve?</p> | g37928 | [
0.03013150580227375,
0.0039800978265702724,
0.004110005684196949,
-0.045327696949243546,
-0.02594156749546528,
-0.06762085855007172,
0.013553249649703503,
-0.030313991010189056,
-0.041814979165792465,
-0.033354502171278,
-0.01999831758439541,
0.023714197799563408,
0.03516577184200287,
-0.0... |
<p>Textbooks typically have nice example plots of of the basis for uniform splines when they're explaining the topic. Something like a row of little triangles for a linear spline, or a row of little humps for a cubic spline.</p>
<p>This is a typical example:</p>
<p><a href="http://support.sas.com/documentation/cdl/e... | g14989 | [
0.02392960712313652,
0.007028152700513601,
0.01715722866356373,
-0.08974546939134598,
-0.06360505521297455,
-0.04673532024025917,
0.03376893699169159,
0.034206319600343704,
-0.021985378116369247,
-0.03853021189570427,
0.03606509044766426,
-0.04443017393350601,
0.06030724570155144,
-0.02712... |
<p>I'm trying to come up with a bivariate poisson model for predicting the outcomes of soccer games.</p>
<p>I have goal scoring rates for the home and away teams, and the probabilities of each score (i.e. 1-0, 2-1, 3-3) being scored (given by bookmakers) for thousands of games. </p>
<p>I am assuming that the probabil... | g59452 | [
-0.010973003692924976,
-0.02279898338019848,
-0.00883089005947113,
-0.060118213295936584,
0.007312601897865534,
-0.041272860020399094,
-0.027370531111955643,
0.008841169998049736,
-0.058060336858034134,
-0.011351492255926132,
0.04516342654824257,
-0.040572427213191986,
0.03282538056373596,
... |
<p>Suppose I have a bunch of people who did a few tests (let's call it tests A). Now I'll do a second test (test B) in order to categorize these people into two categories (that have a pre-defined "true" answer). </p>
<p><em>Note that score from test A can only predict the signal-to-noise ratio of test B. I.e you ca... | g14990 | [
-0.04694591835141182,
-0.035100460052490234,
-0.018940087407827377,
-0.02424396574497223,
0.019728509709239006,
-0.07662757486104965,
-0.005225717090070248,
0.0330633707344532,
-0.033426761627197266,
-0.021348487585783005,
0.014662114903330803,
0.01058220025151968,
0.03426581993699074,
0.0... |
<p>I am conducting a <strong>meta-analysis</strong> from a large number of studies. In each study are <strong>compared weights of two groups</strong> (fishes with and without internal parasite). I am interested if the <strong>weight can explain the presence/absence of a parasite</strong>. From forest plot it seems to b... | g10516 | [
-0.028868474066257477,
-0.006087836809456348,
-0.024982864037156105,
-0.048969294875860214,
-0.0068779862485826015,
0.03355531394481659,
0.03488149866461754,
-0.0009732370381243527,
-0.011145957745611668,
0.028589505702257156,
0.007646281272172928,
0.048935383558273315,
0.010807482525706291,... |
<p>I'd like to understand the Baum-Welch algorithm. I liked this video on the Forward Backward algorithm:
<a href="http://www.youtube.com/watch?v=7zDARfKVm7s&feature=related" rel="nofollow">http://www.youtube.com/watch?v=7zDARfKVm7s&feature=related</a></p>
<p>I'm having trouble coming up with good resources f... | g59453 | [
0.017594337463378906,
0.038530830293893814,
0.005485109053552151,
-0.01959056779742241,
-0.041431862860918045,
-0.035361651331186295,
-0.001782673760317266,
0.046175409108400345,
0.026516348123550415,
-0.01719817705452442,
-0.013733233325183392,
0.06351649016141891,
0.08656768500804901,
0.... |
<p>I consider a first model where the 6 observables (concentrations of metabolites) are fitted on the data set (the experimental measure of these 6 concentrations).
I also have a second model, that is a subset of the first one and models only 4 observables. This second model is fitted on only a part (4 out of 6 concent... | g12535 | [
0.03169430047273636,
-0.014102761633694172,
-0.008987989276647568,
-0.032108649611473083,
0.03294979780912399,
-0.023072777315974236,
-0.03417045623064041,
-0.03543095290660858,
-0.05503299832344055,
-0.023899002000689507,
0.032348815351724625,
0.01506801601499319,
0.07380521297454834,
0.0... |
<p>I am dealing with some data which plotted looks like:</p>
<p><img src="http://i.stack.imgur.com/k118s.png" alt="enter image description here"></p>
<p>I would like to add a level of significance to my claim that the values of the two time courses are different over the latter half of the experiment (data is sampled... | g59454 | [
0.042752303183078766,
-0.031027592718601227,
-0.03623742610216141,
-0.04013773053884506,
0.0011306259548291564,
0.007315745577216148,
0.019746482372283936,
-0.05721661075949669,
-0.0055974433198571205,
0.015884164720773697,
0.04175529256463051,
-0.0003095309075433761,
0.01129903830587864,
... |
<p>I have a large data set of 20M observations with 20+ measures for each observation (people). Additionally I have a set of weights that reflect the racial population where each person lives. For example, from Census data this could be the percentage of population in the zipcode, or tract that is African American, W... | g59455 | [
0.006119477562606335,
-0.005762189626693726,
-0.029541734606027603,
-0.02554953284561634,
0.003910199273377657,
-0.010551034472882748,
0.01393834874033928,
0.001313348882831633,
-0.06781331449747086,
-0.018112415447831154,
0.0012215786846354604,
0.027820125222206116,
0.04516094550490379,
0... |
<ol>
<li>Is it OK to have causals indexed on different base years? Amongst many references, I think the answer is “no”. Is that true? <em>p.360 Wooldridge<a href="http://rads.stackoverflow.com/amzn/click/1111531048" rel="nofollow"> [Introductory Econometrics: A Modern Approach, 5th ed]</a>.</em> says you should have a ... | g59456 | [
0.050275981426239014,
-0.02360147424042225,
0.00879776943475008,
-0.07703748345375061,
0.002616224344819784,
0.0033755225595086813,
0.04447098448872566,
0.033827751874923706,
0.01831560954451561,
0.012309818528592587,
0.07806426286697388,
0.014765688218176365,
0.05172581598162651,
-0.01451... |
<p>I am looking at a two-stage process of diagnosis.</p>
<p>Stage 1 is a screen that identifies people with the diagnosis with some error, Stage 2 is a detailed examination (a gold standard)</p>
<p>In Stage 1, N people were screened, and S were screened positively. </p>
<p>When the S people screened positively were... | g59457 | [
0.052567966282367706,
-0.06282277405261993,
-0.0001818526507122442,
-0.013251453638076782,
0.0006777958478778601,
-0.009883618913590908,
0.0352446548640728,
0.05439884960651398,
-0.0168482456356287,
0.03082403913140297,
0.039181143045425415,
0.043327998369932175,
0.054759539663791656,
0.05... |
<p>I try to (re)produce the results of <a href="http://www.tandfonline.com/doi/abs/10.1080/03610910903528301#preview" rel="nofollow">Austin, PC. (2010).</a>. The question is to obtain an approximated $\beta$, which leads to a specific risk difference(difference of proportions) $p_0 - p_1 = 0.02$, where $p_0$ & $p_1... | g14994 | [
0.0017063793493434787,
-0.0633622258901596,
-0.010820964351296425,
-0.039203133434057236,
0.0033030062913894653,
-0.05339609459042549,
0.0538373701274395,
0.027936652302742004,
-0.08731502294540405,
0.04393872991204262,
-0.011559812352061272,
0.058765776455402374,
0.020707055926322937,
-0.... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.