question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>A linear mixed effects model allows you to specify random subject-level effects, or a (non-zero) covariance structure for within-subject residuals, or both. I've read a number of separate explanations of subject-level random effects and residual covariance structures, but I don't understand how these relate to each ... | g62992 | [
0.020899370312690735,
-0.06637701392173767,
0.016309361904859543,
-0.03365202248096466,
-0.034262675791978836,
0.05380678176879883,
0.09288398921489716,
0.02581174485385418,
-0.006876514758914709,
-0.05564877390861511,
0.01817391626536846,
-0.033198658376932144,
0.007908123545348644,
-0.04... |
<p>Suppose I make measurements of variable $P$ and a sequence of variables $D^1, D^2, \ldots$. There is correlation with $P$ and $D^i$, but not with $D^i$ and $D^j$.</p>
<p>I can make a detection metric that looks like:
$$\boldsymbol{z} = [P, D^1, D^2, \ldots, D^N]^T$$</p>
<p>or of the form
$$\boldsymbol{z}^1 = [P, D... | g20411 | [
0.00046491113607771695,
-0.023506231606006622,
-0.023905660957098007,
-0.021277716383337975,
0.018181471154093742,
-0.006321629509329796,
0.05055617168545723,
0.000792903418187052,
-0.01131158322095871,
-0.006473238579928875,
-0.023688960820436478,
0.03524256497621536,
0.012323027476668358,
... |
<p>In a MCMC implementation of hierarchical models, with normal random effects and a Wishart prior for their covariance matrix, Gibbs sampling is typically used.</p>
<p>However, if we change the distribution of the random effects (e.g., to Student's-t or another one), the conjugacy is lost. In this case, what would be... | g49658 | [
0.014227251522243023,
-0.026550790295004845,
-0.004308938980102539,
-0.06993716210126877,
-0.037285976111888885,
-0.007899410091340542,
0.014015618711709976,
0.056454721838235855,
-0.007633864413946867,
0.03344481810927391,
0.03311410918831825,
0.049130700528621674,
0.008071301504969597,
0... |
<p>I have a problem trying to properly phrase my results.</p>
<p>I utilized:</p>
<p>$$D =\frac{(\text{M}_{2e} –\text{M}_{2c}) – (\text{M}_{1e}-\text{M}_{1c})}{\text{SD}_{1\text{pooled}}}$$</p>
<p>for pooled SD I used:</p>
<p>$$\text{SD}_{1\text{pooled}} = \sqrt{\left((n_1-1)s_1^2 + (n_2-1)s_2^2\right)\big /(n_1+n_2... | g46343 | [
-0.00669099623337388,
-0.04656435176730156,
-0.024349402636289597,
-0.07228315621614456,
0.012150095775723457,
-0.008965256623923779,
0.10908546298742294,
0.006476001348346472,
-0.010711838491261005,
-0.004791935905814171,
-0.010881277732551098,
0.07669197022914886,
0.02279309183359146,
0.... |
<p>I am trying to estimate a longitudinal model in R in which there are several random intercepts that are correlated with each other, and the data are non-nested. For example, consider a simple longitudinal model in which student test scores are regressed on three random intercepts, one random school effect, one rand... | g62993 | [
-0.02201101742684841,
-0.05521620810031891,
-0.004209741018712521,
-0.044197529554367065,
0.04025059565901756,
-0.004585621412843466,
0.051417913287878036,
0.00034032916300930083,
-0.023062771186232567,
-0.01839856058359146,
0.043707847595214844,
0.026336342096328735,
-0.020144321024417877,
... |
<p>I need to analyze data regarding an item based on a Likert scale. Field data was arranged in Excel using tables that show the frequency of answers among respondents.
What is the best approach to enter data in the statistical software in order to analyze it? </p>
<p>An example of what I have in Excel is attached. I... | g46346 | [
0.03770530968904495,
0.03645017370581627,
0.020386867225170135,
-0.05455876141786575,
-0.026260588318109512,
-0.017195187509059906,
0.011734044179320335,
-0.022973211482167244,
-0.07806850224733353,
-0.00893890019506216,
0.019315162673592567,
-0.0012508138315752149,
0.04317755624651909,
-0... |
<p>I have two groups with small number of n (less than 10) where some observations are replicates for each other, some are paired difference observations, and some are completely independent. For example:</p>
<pre><code>Group I Group II
A <--paired--> B
C (unpaired)
D <--paired--> E
F <-| replica... | g49029 | [
-0.035211287438869476,
0.005306928884238005,
0.002701899968087673,
-0.05844344571232796,
0.009986099787056446,
-0.02153620310127735,
-0.016223616898059845,
0.02901718020439148,
-0.03661349043250084,
-0.03232940658926964,
-0.0033438866958022118,
0.04991142824292183,
-0.012386642396450043,
0... |
<p>I would like to fit a general N-order polynomial of two or more variables. For example, consider (for reference) the general second-order polynomial in two variables $x$ and $y$:</p>
<p>$$\beta_{00}+\beta_{01}y^1+\beta_{02}y^2+\beta_{10}x+\beta_{11}xy+\beta_{12}xy^2+\beta_{20}x^2+\beta_{21}x^2y+\beta_{22}x^2y^2.$$<... | g62994 | [
0.014129545539617538,
-0.026531025767326355,
-0.007605189457535744,
-0.024120595306158066,
-0.020246924832463264,
-0.04649720340967178,
-0.04694698378443718,
-0.008862562477588654,
-0.01525093149393797,
0.008122668601572514,
-0.002327637281268835,
0.015235291793942451,
-0.04700160026550293,
... |
<p>I am estimating a probit in jags on a time series cross sectional data set (country years) with 5 covariates, 4 of which are lagged, so the first observation for each country will be missing on those 4 variables. There is some scattered missingness elsewhere in the data, but nothing too bad. All of the variables are... | g62995 | [
0.04156528040766716,
-0.037481639534235,
-0.024542292580008507,
-0.05572211742401123,
0.05966213345527649,
0.022052664309740067,
-0.00719906110316515,
-0.03923364728689194,
-0.06023840606212616,
0.008591772057116032,
0.02686171792447567,
0.019125575199723244,
0.011208536103367805,
0.035863... |
<p>I am having an issue getting my head around this question as well. Gale-force winds occur on the average of 0.7 times every 54 hours. For an interval of 110 hours whats the probability r = 2?</p>
<p>I believe I should solve it with Poisson Distribution (as it is in this weeks lesson, and question references using ... | g46568 | [
0.020358707755804062,
0.0021447197068482637,
0.001154417172074318,
-0.058053579181432724,
0.017400695011019707,
-0.006842015311121941,
0.025806622579693794,
0.023893622681498528,
-0.02580842562019825,
-0.017862476408481598,
-0.0075255027040839195,
0.017871417105197906,
0.008274121209979057,
... |
<p>In Andrew Ng's online machine learning course in the part about neural nets for classification the following convex cost function is given:
$$\text{cost} = -y\log(h_0(x)) - (1-y)\log(1-h_0(x))$$
which is predicated on the output labels being either 1 or 0 (a sigmoid activation function). I would like to code a NN cl... | g20419 | [
0.02319672890007496,
-0.038619257509708405,
0.012440545484423637,
-0.03177429735660553,
0.008066660724580288,
-0.09109041839838028,
0.062023360282182693,
0.006874429062008858,
-0.004574362188577652,
0.002791651524603367,
-0.029753603041172028,
0.05107482895255089,
0.06790346652269363,
-0.0... |
<p>25 patients receive treatment, and they each get a difference score (After-Before). 18 of them get positive scores. I would like to test the null hypothesis that p=0.5.</p>
<p>I know that <code>1-pbinom(17,25,0.5)</code> gives me the probability of 18 or more patients getting a positive score. My question is, to ca... | g20420 | [
0.01251094602048397,
0.02191522903740406,
-0.006592764984816313,
-0.005098006688058376,
0.02141341008245945,
-0.0312863290309906,
0.030704287812113762,
0.04967688024044037,
-0.06580785661935806,
-0.04504438489675522,
-0.05662817135453224,
0.06701667606830597,
0.04182190075516701,
-0.006913... |
<p>I read that the $Cov(\hat{\beta})=\sigma^2(Z'Z)^{-1}$, where $\hat{\beta}=(Z'Z)^{-1}Z'y$. However, I have yet been unable to find a proof of this fact online. Could anyone please provide a proof and/or a reference?</p> | g49871 | [
-0.012451066635549068,
-0.013783801347017288,
-0.006602680776268244,
0.0036470505874603987,
0.0641743466258049,
-0.03738928958773613,
0.10745082050561905,
-0.025828072801232338,
0.0056007253006100655,
0.02241607755422592,
-0.05480678752064705,
0.06924504786729813,
-0.01322463620454073,
0.0... |
<p>Does anyone know a good reference about how to use seemingly unrelated regressions to test for teh difference in coefficients across groups?</p> | g62996 | [
-0.025355355814099312,
-0.03974831849336624,
-0.014280591160058975,
-0.038472313433885574,
0.04177327826619148,
-0.06264230608940125,
0.020321747288107872,
0.0222452562302351,
-0.009113463573157787,
0.017250927165150642,
-0.011138411238789558,
0.043412450700998306,
0.028895806521177292,
0.... |
<p>How can I generate binary time series such that:</p>
<ol>
<li>Average probability of observing 1 is specified (say 5%);</li>
<li>Conditional probability of observing 1 at time $t$ given the value at $t-1$ ( say 30% if $t-1$ value was 1)?</li>
</ol> | g34593 | [
-0.03363875672221184,
0.03409550338983536,
0.006641846615821123,
-0.04297097027301788,
0.001565302605740726,
-0.011585377156734467,
0.026559820398688316,
0.007005559746176004,
-0.05583707243204117,
-0.03353862464427948,
0.01860572211444378,
0.027054453268647194,
0.033937934786081314,
0.043... |
<p>I have two time-series, <code>x</code> and <code>y</code>. I would like to prewhiten <code>x</code> by fitting an ARMA(p,q) (or in my case ARMA(1,1)) process and then use the coefficients to filter <code>y</code>. This seems like a pretty standard thing to want to do. However, the <code>stats:::filter</code> functi... | g39630 | [
0.04675838351249695,
-0.040889300405979156,
0.008578887209296227,
-0.024528443813323975,
0.02359701134264469,
-0.03787156194448471,
0.059087395668029785,
-0.0023995423689484596,
0.009157582186162472,
0.02880653366446495,
0.008779729716479778,
0.06611113995313644,
0.08492004871368408,
0.005... |
<p>I'm interested in any references for simulating ordinal random variables to be used in a Bayesian (multilevel) analysis. </p> | g34595 | [
-0.021426090970635414,
-0.00836191512644291,
-0.00937785767018795,
-0.08249209821224213,
-0.053940724581480026,
-0.05155554413795471,
-0.026678891852498055,
-0.03471992909908295,
-0.0184263214468956,
0.026886243373155594,
0.01697026751935482,
0.0001965005067177117,
0.04357593134045601,
0.0... |
<p>How can internal consistency reliability of a test and of individual test items be quantified in Item Response Theory models? I know I can resort to Classical Test Theory, Cronbach's alpha, and other measures, but is there a way to characterize reliability within IRT?</p> | g39634 | [
-0.035244353115558624,
-0.05612919107079506,
-0.01699889823794365,
0.02046634815633297,
0.03769398480653763,
0.04386329650878906,
0.012233718298375607,
0.013095363043248653,
-0.0035597148817032576,
0.006556735839694738,
-0.017337309196591377,
-0.002414271468296647,
-0.007285092957317829,
-... |
<p>I have the model $Y_i=\exp(\beta_0 + \beta_1 X_i +\beta_2 Z_i) + u_i$ where we assume $\mathbf{E}[u_i|X_i,Z_i]=0$ and $Var(X_i)>0,Var(Z_i)>0$, and I need to show that $\beta_0,\beta_1,\beta_2$ are identified. I know that it's possible to take a log transformation somehow to make it linear but I can't seem to f... | g62997 | [
0.025848038494586945,
-0.03268341347575188,
-0.040442947298288345,
-0.003594234585762024,
0.07618458569049835,
-0.034254588186740875,
0.039289798587560654,
0.02519606240093708,
-0.027525069192051888,
-0.01113478560000658,
-0.09010498225688934,
0.0447218120098114,
0.03479747474193573,
0.044... |
<p>Let's say I have a large set of $S$ values which sometimes repeat. I wish to estimate the total number of <em>unique</em> values in the large set.</p>
<p>If I take a random sample of $T$ values, and determine that it contains $T_u$ unique values, can I use this to estimate the number of unique values in the large ... | g20431 | [
-0.04990292713046074,
0.0347147211432457,
-0.0074678142555058,
-0.04168564826250076,
-0.04290364682674408,
-0.05773937702178955,
0.008193977177143097,
-0.0005962863797321916,
-0.017649924382567406,
0.005336971953511238,
-0.05135232210159302,
0.02015736699104309,
-0.0059663522988557816,
0.0... |
<p>I am looking for some probability inequalities for sums of unbounded random variables. I would really appreciate it if anyone can provide me some thoughts.</p>
<p>My problem is to find an exponential upper bound over the probability that the sum of unbounded i.i.d. random variables, which are in fact the multiplica... | g62998 | [
-0.0436113215982914,
0.0032938625663518906,
-0.0025158985517919064,
-0.05037691071629524,
-0.02482173778116703,
-0.005165786482393742,
0.03534894064068794,
-0.007369115948677063,
-0.03573150560259819,
0.013056005351245403,
-0.0314316563308239,
0.01946292631328106,
0.013229898177087307,
0.0... |
<p>I have a table with a couple hundred columns and a few hundred thousand rows and want to determine which combination of 5-10 columns best correlate with a target column.</p>
<p>I have SQL Server and Excel but no budget beyond that.</p>
<p>My current plan is:</p>
<ol>
<li>Pull the table into Excel</li>
<li>Use the... | g62999 | [
0.012496802024543285,
-0.012754200026392937,
0.024213217198848724,
-0.03918486833572388,
0.04045238718390465,
-0.06513362377882004,
0.005030953325331211,
0.007800237741321325,
-0.024779243394732475,
0.0067804669961333275,
0.031265340745449066,
0.01614043302834034,
0.07936292141675949,
-0.0... |
<p>We work on cervical cancer detection and we started accumulating data in 2006 by performing HPV testing on all our samples. We have accumulated a data set with almost 400,000 women. Data enters the database on a daily basis. Most women come for a yearly smear so most women are more than one time in the database (2-1... | g63000 | [
-0.005178436636924744,
-0.04697665944695473,
-0.01112562045454979,
0.03149939700961113,
-0.0013265919405966997,
-0.034883517771959305,
0.014949999749660492,
0.01225739810615778,
0.0020739042665809393,
0.004529798869043589,
0.02542695589363575,
0.0068489378318190575,
0.06981796026229858,
-0... |
<p>I was wondering if anybody had experience in how to set the knot points when using cubic regression splines.</p>
<p>Some background: I have a response and predictor variable, and I want to determine the trend relationship between the two. To see what it looks like without making too many assumptions, I've fit a smo... | g39639 | [
0.04803900048136711,
-0.04381505027413368,
-0.010118920356035233,
-0.04486624896526337,
0.0018554837442934513,
-0.007263023406267166,
0.0778009444475174,
0.065778948366642,
-0.04156230762600899,
0.009362095035612583,
0.004705615341663361,
0.0161887314170599,
0.06611484289169312,
-0.0440787... |
<p>I'm sure this is a pretty standard statistics question, but I'm no expert... I'm running an A/B test on my website to see if a change results in users adding more content. So there are 2 basic things I'm looking at; the # of users adding at least 1 piece of content and the total # of pieces of content added by all... | g63001 | [
-0.023293547332286835,
0.012454502284526825,
-0.007458698470145464,
-0.02028709091246128,
-0.01146945171058178,
-0.04876115918159485,
0.04120543599128723,
0.01812799833714962,
0.014926135540008545,
-0.004384392406791449,
0.032385069876909256,
0.006513240747153759,
0.044302307069301605,
0.0... |
<p>This question is motivated by a issue regarding network motifs. To determine if a (connected, induced) subgraph $H$ occurs with significantly high frequency in an input network $G$, we generate an ensemble of comparison networks similar to $G$ and count the number of occurences of $H$ in them. Thus we obtain the n... | g63002 | [
-0.009169782511889935,
0.03548390418291092,
-0.025757906958460808,
-0.05090227723121643,
0.015082583762705326,
-0.06203289330005646,
0.05133287236094475,
-0.008020143024623394,
-0.044321607798337936,
0.0074081094935536385,
-0.05335260555148125,
0.04063836485147476,
-0.0027023276779800653,
... |
<p>In a practice exam I encountered a question about the standard error of a sample (calculating the mean order size of a random sample of 100 customers of a paper firm). A researcher (the subject of this question) advised against increasing the sample size because -although it would decrease the standard error- it al... | g6294 | [
0.0013590437592938542,
0.05516643077135086,
0.009985871613025665,
-0.009410121478140354,
-0.029803233221173286,
-0.004073522984981537,
-0.02054431661963463,
0.031982868909835815,
-0.0027324804104864597,
0.0349152535200119,
0.05450898036360741,
-0.003240222344174981,
0.020635521039366722,
-... |
<p>I work in experimental economics, labor and housing market.</p>
<p>I am trying to answer the following question: why do researchers use matched pairs of applications in labor market correspondence tests (typically in hiring context), whereas they use a completely randomized approach in the housing market correspond... | g63003 | [
0.028854958713054657,
-0.048552073538303375,
0.010028315708041191,
0.0021180177573114634,
-0.010879425331950188,
-0.0018843244761228561,
0.03839715197682381,
0.059201929718256,
0.028127705678343773,
0.00983707420527935,
0.03217596560716629,
0.0036586520727723837,
0.0077583156526088715,
0.0... |
<p>I would like (in the distant future) to teach statistics to kids. For that matter, I'd be happy to know of software (obviously I am tending towards FOSS), or webapps, that are helpful in explaining statistical/probabilistic ideas to kids (or adults for that matter).</p>
<p>This can be used either by the instructor... | g39643 | [
0.03838623687624931,
-0.022580023854970932,
0.027933349832892418,
-0.006486600264906883,
-0.07826389372348785,
0.005208930466324091,
-0.02132510207593441,
-0.045110542327165604,
-0.019575489684939384,
-0.07013420015573502,
0.03670354187488556,
-0.03776854649186134,
0.05833527818322182,
0.0... |
<p>I am studying the effect a certain chemical and age on an outcome. As variables, <code>age</code> is a factor of with levels 1, 2, and 3 and <code>covar1</code> is continuous. </p>
<p>After fitting the model</p>
<pre><code>mod1 <- glm(out1 ~ covar1*age, family=poisson, data=df)
</code></pre>
<p>The estimates... | g20441 | [
-0.05275988578796387,
-0.04541110247373581,
-0.005115125793963671,
-0.05302931368350983,
0.029265761375427246,
0.03227880597114563,
0.07635299116373062,
0.034621983766555786,
-0.045015186071395874,
-0.02231748402118683,
-0.05460922420024872,
0.003820687998086214,
0.028597760945558548,
-0.0... |
<p>Is there such thing as a procedure to 'fit' an random walk? I have done analysis on the increments of my data and have fitted several distributions and performed goodness-of-fit tests. With this done, is that the random walk model 'fitted' and then I should test the validity of the model?
Something that looks intere... | g620 | [
0.0016122193774208426,
-0.0101740388199687,
-0.0058129578828811646,
-0.02381099760532379,
-0.05195656046271324,
0.0064314305782318115,
0.060889966785907745,
0.009248638525605202,
-0.042217954993247986,
-0.029398856684565544,
-0.0009087561629712582,
-0.04111391305923462,
0.05353337526321411,
... |
<p>I'm running an experiment where we are taking 1500 of a certain type of product and changing the price of half of them to see if this influences sales. There are 5 categories on which I will be comparing the data that are exponentially distributed (i.e. sales volume over time for different regions).</p>
<p>I need t... | g63004 | [
-0.027222486212849617,
-0.007601588498800993,
-0.013960777781903744,
-0.04366219416260719,
0.012600178830325603,
-0.03696368262171745,
0.05858897790312767,
-0.00024349390878342092,
-0.03655189648270607,
0.037402402609586716,
0.03544953092932701,
0.030100658535957336,
0.010224970988929272,
... |
<p>I want to make a GLM with a quasipoisson response distribution. My response variable is inflorescences by plant and my explanatory variable is coverage. For inflorescence counts, I used the average from four subsamples counted from each plant. However, somebody recommended that I use the original data. In this way I... | g20444 | [
0.023882994428277016,
-0.022055525332689285,
-0.023606138303875923,
-0.0346849299967289,
0.0023752572014927864,
-0.012573975138366222,
0.030146611854434013,
0.0006051796954125166,
-0.04547141119837761,
-0.07572391629219055,
-0.03738485276699066,
0.014696505852043629,
0.07106315344572067,
0... |
<p>I'm measuring the influence of the use of male gaze and nudity in magazines to see if girls self-objectify or not. Now, I want to determine the influence of age.</p>
<pre><code>Independent variables: male gaze (yes / no)
clothes (few clothes / lots of clothes)
Dependent variable: Se... | g63005 | [
-0.04910406470298767,
0.02896360121667385,
-0.012138002552092075,
-0.06587906181812286,
-0.029654493555426598,
0.04535989090800285,
0.08910209685564041,
0.028952516615390778,
0.00681521138176322,
-0.013253960758447647,
-0.03230955824255943,
0.005193864461034536,
0.04753104969859123,
0.0627... |
<p>Inspired by this: <a href="http://pss.sagepub.com/content/22/11/1359" rel="nofollow">http://pss.sagepub.com/content/22/11/1359</a></p>
<p>In the context of open-ended data collection where the necessary sample size cannot be properly estimated, for the purpose of a frequentists test;</p>
<p>I understand that a sto... | g63006 | [
0.03718934580683708,
-0.002765943529084325,
0.00744728883728385,
-0.071224145591259,
-0.04414811730384827,
0.03621148690581322,
0.03783411532640457,
-0.007410706952214241,
-0.040934592485427856,
-0.029981015250086784,
0.0381840281188488,
0.015172487124800682,
-0.028769811615347862,
0.01571... |
<p>As I'm doing a competing risks survival analysis, I need to construct a cumulative incidence graph rather than a Kaplan-Meier survivor curve. However, in Stata, the command to construct this graph is only available for continuous data so has anyone had experience in constructing a CIF using discrete time data and ho... | g63007 | [
0.04323563352227211,
-0.04953008145093918,
0.004428770858794451,
-0.006694719661027193,
-0.02597847394645214,
-0.04975677654147148,
0.04687952995300293,
0.011463942937552929,
-0.04211847111582756,
-0.07240614295005798,
0.013195676729083061,
-0.03623227775096893,
0.03762207180261612,
-0.041... |
<p>I am trying to estimate a model of occupational choice with three choices. Are there any alternatives to using the multinomial logistic regression when handling such unordered categorical outcomes?</p>
<p>When dealing with binary dependent variables there seems to be several choices such as the LPM model as well as... | g20447 | [
-0.0679345354437828,
0.03914400935173035,
0.013193069957196712,
-0.028796089813113213,
-0.03582126274704933,
0.007364382967352867,
-0.0743575170636177,
-0.049270641058683395,
0.01595739834010601,
0.018545951694250107,
-0.017520049586892128,
-0.04303164780139923,
0.04438891261816025,
0.0180... |
<p>I have a number of vectors of categorical data (ex. {'re','ty','cf', ...} ) and I want to perform an unsupervised learning on them. I came across <code>self-organizing map</code> technique and I am trying to see if I can apply this method on my data. The vectors that I have are not similar in size and I was thinking... | g20448 | [
-0.062344323843717575,
0.007236827164888382,
0.024863123893737793,
-0.07267551124095917,
-0.02577233500778675,
-0.04702175781130791,
-0.00291419611312449,
-0.006760492920875549,
-0.054713957011699677,
0.0018285324331372976,
0.010445904918015003,
-0.025530502200126648,
0.06107135862112045,
... |
<p>The <a href="http://yann.lecun.com/exdb/mnist/" rel="nofollow">MNIST dataset</a> is a standard benchmark data set of digit images.
MNIST stands for 'Mixed National Institute of Standards and Technology'.</p>
<p>The <a href="http://www.cs.nyu.edu/~ylclab/data/norb-v1.0/" rel="nofollow">NORB dataset</a> is a commonly... | g63008 | [
0.022487396374344826,
-0.027079328894615173,
-0.029394520446658134,
-0.09245090186595917,
0.008808061480522156,
-0.02642255648970604,
0.04083015397191048,
0.040370918810367584,
-0.03102456033229828,
0.00379613833501935,
0.011406072415411472,
-0.007192387245595455,
0.06666756421327591,
0.00... |
<p>I have been asked an interesting modelling question by a clinician. The outcome he is trying to predict whether a particular type of cancer will occur. One of the covariates is an indicator variable if the patient previously had another kind of cancer. Other covariates are cancer diameter and margin size of this pri... | g10264 | [
0.04501309618353844,
-0.04617077484726906,
0.003568560816347599,
-0.05786900594830513,
-0.04447295889258385,
-0.006929777562618256,
0.029923174530267715,
-0.004875022452324629,
-0.026397421956062317,
-0.03023533895611763,
0.0419287383556366,
0.01964430883526802,
0.05322467163205147,
-0.010... |
<p>I am asking this question in context to section 4.1 in this paper:
security control methods for statistical Database
(<a href="http://www.utdallas.edu/~muratk/courses/privacy08f_files/stat_database_sec.pdf" rel="nofollow">http://www.utdallas.edu/~muratk/courses/privacy08f_files/stat_database_sec.pdf</a>)</p>
<p>As... | g63009 | [
0.04783417284488678,
0.018607208505272865,
-0.01367982942610979,
0.021205009892582893,
0.007059257943183184,
0.003709549317136407,
0.059421323239803314,
0.03842570260167122,
-0.024311792105436325,
0.00007851838745409623,
0.0027425249572843313,
0.04017935320734978,
0.059938617050647736,
-0.... |
<p>I would like to create a composite scale for different attitudes by calculating the mean score from different items on a questionnaire. Most of the items use Likert scales however some of the items on the questionnaire just use yes/no answers. Is it still possible to combine these scores to create a composite scal... | g63010 | [
-0.022232800722122192,
-0.01584015227854252,
-0.0017805517418310046,
-0.0331287607550621,
0.04633481428027153,
0.014540566131472588,
-0.030826522037386894,
0.006390910595655441,
-0.020615022629499435,
-0.02031920850276947,
-0.00007183873822214082,
-0.004958853591233492,
0.030260872095823288,... |
<p>Suppose I want to model the sales of Coke sold at WalMart for a particular state in the U.S. Suppose I only have access to a year's worth of weekly sales data for that particular store. I want to model the sales of Coke. My question pertains to the modeling of catastrophic events or rare events. For example, suppose... | g20454 | [
-0.02209717407822609,
0.02167707122862339,
-0.001674322527833283,
-0.032740551978349686,
-0.006643372587859631,
0.002737751230597496,
0.01261376217007637,
0.03698088601231575,
-0.011742481961846352,
0.008345727808773518,
0.024724140763282776,
-0.014891285449266434,
0.08249881118535995,
-0.... |
<p>Why is it that in a normal t-test we have n-2 degrees of freedom while in the SAS output, and consequently the confidence interval constructed from this output, we end up using our 'error' degrees of freedom. As an example say we have 1 DF for our linear model and 14 DF 'error'. Then there are 15 DF in total. How... | g63011 | [
0.026738477870821953,
-0.009236784651875496,
-0.0007469422416761518,
0.027096185833215714,
-0.007869873195886612,
-0.01056866254657507,
0.061800766736269,
-0.0017947364831343293,
-0.04312320798635483,
-0.012261859141290188,
0.02137327380478382,
-0.01851758547127247,
0.010418162681162357,
-... |
<p>I am investigating a discrepancy between male and female self reports of sexual experiences. The original survey consists of a female version (asking about victimization) and a male version (asking about perpetration). Typically, when given the original version, female's reported rates of victimization are about 2... | g63012 | [
0.04912889748811722,
-0.02773417718708515,
0.008854900486767292,
-0.02102813310921192,
0.0021833686623722315,
-0.02365800552070141,
0.002674388000741601,
0.015026554465293884,
0.027120336890220642,
-0.019170913845300674,
0.01466331910341978,
0.014060037210583687,
-0.005555823910981417,
0.0... |
<p>I read about using scoring rules to evaluate the performance of predictive models. In the Wikipedia article about the <a href="http://en.wikipedia.org/wiki/Brier_score" rel="nofollow">Brier score</a>, it is stated:</p>
<blockquote>
<p>The Brier score is appropriate for binary and categorical outcomes
that can b... | g20455 | [
-0.004550033714622259,
0.02208276465535164,
0.007789358962327242,
-0.050189029425382614,
0.02747984416782856,
-0.061160095036029816,
-0.011699624359607697,
0.014609391801059246,
-0.0339985266327858,
-0.01804099604487419,
0.0390370674431324,
0.010680456645786762,
0.03304661065340042,
-0.013... |
<p>I have two more questions. Why <a href="http://www.statsoft.com/textbook/elementary-statistics-concepts/#What%20is%20%22statistical%20significance%22%20%28p-level%29" rel="nofollow">Statsoft's textbook says</a> that</p>
<blockquote>
<p>the p-value represents the probability of error that is involved in
acceptin... | g20456 | [
0.04262728616595268,
0.04915822669863701,
-0.009869895875453949,
-0.003945829812437296,
0.05905130133032799,
-0.019514797255396843,
-0.006430039182305336,
0.016704155132174492,
-0.054007939994335175,
-0.0033212839625775814,
-0.010524380020797253,
0.012904701754450798,
0.02069130912423134,
... |
<p>Good evening,</p>
<p>I am attempting the following question where I was able to successfully find the R-square (the coefficient of determination) at 0.8945.</p>
<p>While I am able to identify this, my weak foundation in regression leave me puzzled to what this actually means. Appreciate some advice please.</p>
<b... | g28526 | [
0.029151756316423416,
0.005140285007655621,
-0.01598108559846878,
-0.04451438784599304,
-0.005124224815517664,
-0.05163275822997093,
0.10535608977079391,
-0.020741602405905724,
-0.016843780875205994,
-0.004483960103243589,
-0.060811903327703476,
0.0023400583304464817,
0.04073486104607582,
... |
<p>I trained classifier using ada.</p>
<p>Now I executed:</p>
<pre><code>predict(adaDol,newdata=cords())
</code></pre>
<p>and received response:</p>
<pre><code> [1] FALSE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
[25] TR... | g13008 | [
-0.02688959799706936,
-0.019407227635383606,
0.04280022904276848,
-0.035719603300094604,
0.007076467853039503,
-0.028450656682252884,
0.07300584763288498,
-0.015819063410162926,
-0.018885741010308266,
-0.09753423929214478,
-0.059407006949186325,
0.04556221887469292,
0.10176189243793488,
0.... |
<p>I am now plotting some bars and pictures for use in presentation.
Really interested in different ways of showing confidence intervals on the plots.</p> | g63013 | [
0.008025847375392914,
0.01665584184229374,
-0.02403826266527176,
-0.038220636546611786,
-0.03478984534740448,
-0.014880502596497536,
0.04156840220093727,
-0.0035792377311736345,
-0.06021321564912796,
-0.027661411091685295,
0.039738137274980545,
0.0005169766373001039,
0.024960294365882874,
... |
<p>I'm working on two identical set of items that only differ in their frequency-of-occurence dimension (in the first is max.7 while in the second is max.4). They are both fit with the Generalised partial credit model. I would like to understand if the scale has a better fit with 7 categories or with 4. Is there a test... | g63014 | [
0.029886852949857712,
-0.002137923613190651,
0.00204872852191329,
-0.03791594132781029,
-0.0027625004295259714,
-0.006768859922885895,
0.024216709658503532,
-0.01859992742538452,
-0.0479692704975605,
-0.014283529482781887,
0.00182526174467057,
-0.022606294602155685,
0.023631161078810692,
0... |
<p>I try to estimate an underfloor pipe position based on a temperature distribution on a surface of the floor.</p>
<p>I know there is the pipe emitting a hot temperature all way along. I can measure a distribution of this temperature in a rectangular room. I know that the pipe can be in two shapes only as a straight ... | g63015 | [
0.041467659175395966,
-0.029317613691091537,
-0.01880938746035099,
-0.06579498946666718,
-0.029862578958272934,
-0.006810071878135204,
0.0028615568298846483,
0.012319894507527351,
-0.07528620213270187,
-0.03238010033965111,
0.01143996324390173,
0.008618882857263088,
-0.0006070795352570713,
... |
<p>Let's say I have a data set (with a binary DV) which I used a generalized linear mixed-effects model on. I am currently trying to run a simulation-based power analysis to determine the sample size I should try to collect for a replication attempt. </p>
<p>I know about the <a href="http://www.inside-r.org/packages/c... | g63016 | [
-0.01248995866626501,
-0.016956135630607605,
-0.017469065263867378,
-0.07996948808431625,
-0.05605471506714821,
-0.027205459773540497,
-0.01842554099857807,
0.006237493362277746,
-0.05698841065168381,
-0.022152600809931755,
0.007093239575624466,
0.011747474782168865,
0.027811763808131218,
... |
<p>I have been trying unsuccessfully for a while to understand and setup an inference problem and use EP with it. I have tried to extract a simple case to highlight he issue. I hope someone will be kind enough to offer some insight into this.</p>
<p>I have a graphical model as shown in the image below:</p>
<p><img sr... | g63017 | [
0.028357965871691704,
-0.047374121844768524,
-0.012828627601265907,
-0.0607806034386158,
0.010709399357438087,
-0.02128106914460659,
0.03141845390200615,
0.029594801366329193,
-0.02659774012863636,
0.023691261187195778,
0.024333825334906578,
0.025850141420960426,
-0.010912114754319191,
-0.... |
<p>I'm using Isomap to reduce the dimensionality of my data. </p>
<p>Isomap use geodesic distance rather than Euclidean distance to perform a MDS.</p>
<p>Now I want to reconstruct my original data with a lower dimensional coordinate. How can I do that? </p>
<p>When the lower dimensional coordinate lies on a data poi... | g63018 | [
0.06623009592294693,
-0.023431802168488503,
-0.01696649007499218,
-0.052394431084394455,
0.0022375741973519325,
0.0214058980345726,
0.009620034135878086,
0.026088785380125046,
-0.05533863604068756,
-0.07563045620918274,
0.01472595427185297,
0.018117129802703857,
0.09438592940568924,
-0.032... |
<p>I'm plotting a bunch of survivor and hazard curves.</p>
<p>The lognormal survivor function is: </p>
<p>$S(t)=1-\Phi(\frac{log(t)-\mu}{\sigma}) $</p>
<p>Where $\mu$ is the scalar parameter.</p>
<p>From a website (<a href="http://www.itl.nist.gov/div898/handbook/eda/section3/eda3669.htm" rel="nofollow">http://www.... | g20469 | [
0.012591414153575897,
-0.022570740431547165,
-0.007495628669857979,
-0.047202836722135544,
0.049401119351387024,
0.043966736644506454,
-0.03224129229784012,
0.00878893118351698,
-0.07211823761463165,
0.004983211867511272,
-0.021843738853931427,
0.028310593217611313,
0.06057417020201683,
-0... |
<p>I am trying to prove that the observed information matrix evaluated at the weakly consistent maximum likelihood estimator (MLE), is a weakly consistent estimator of the expected information matrix. This is a widely quoted result but nobody gives a reference or a proof (I have exhausted I think the first 20 pages of ... | g63019 | [
0.027741173282265663,
-0.045657142996788025,
-0.01825128123164177,
-0.026268556714057922,
-0.0471595823764801,
-0.020196713507175446,
0.020503152161836624,
0.030054733157157898,
-0.02684781700372696,
0.006352732423692942,
-0.01714162528514862,
-0.006417553406208754,
-0.01609520986676216,
0... |
<p>I have been using a/b testing in order to optimise changes I make to my websites. Previously, I have set a single conversion goal and have ended up with a conversion rate for each group. I then used R (with the <code>power.prop.test</code> function) to calculate the power and significance of the change in conversi... | g63020 | [
-0.009190450422465801,
-0.006810932420194149,
-0.021190796047449112,
-0.001994183985516429,
-0.019959867000579834,
-0.06054665893316269,
0.03757042437791824,
0.04109344258904457,
-0.05205114930868149,
-0.010584162548184395,
0.08117668330669403,
0.01979932188987732,
0.06568610668182373,
0.0... |
<p>In my experiment, individuals assign probabilities to the likelihood of future events, and update their forecasts as frequently as they like. Most questions stay open (receiving new forecasts) for months. Forecasters are placed in different experimental conditions. Some forecast in isolation, some can observe fo... | g20470 | [
0.009671990759670734,
-0.05734902247786522,
0.008812491782009602,
-0.013309799134731293,
0.0056649683974683285,
-0.02750294841825962,
0.006369391456246376,
0.0267132967710495,
-0.08255811780691147,
0.0011245349887758493,
0.05256100371479988,
0.0071562109515070915,
0.015608098357915878,
0.0... |
<p>I have monthly returns data going back to 1991 and I'm trying to work out if the data has a tendency to mean revert over time. In order to work this out I've used the Augmented Dickey Fuller test on GRETL - an example of my output is here:
<img src="http://i.stack.imgur.com/ifOUO.jpg" alt="output"></p>
<p>I've als... | g63021 | [
0.021776583045721054,
-0.014444730244576931,
-0.03481128811836243,
-0.03641899675130844,
0.025412477552890778,
0.007829415611922741,
0.06437236815690994,
0.005274213384836912,
-0.05582284927368164,
-0.05893297865986824,
-0.006567847914993763,
0.10492871701717377,
0.07641739398241043,
-0.01... |
<p>Why differencing a normal, i.i.d. time series $X$, generates a negatively correlated series $Y$?</p>
<pre><code>> Acf(rnorm(5000, 0, 40))
> Acf(diff(rnorm(5000, 0, 40)))
</code></pre>
<p><img src="http://i.stack.imgur.com/c1FXP.png" alt="enter image description here"></p>
<p>I stumbled on this problem while... | g63022 | [
0.03759653493762016,
-0.02908770740032196,
-0.006714457646012306,
-0.05035378038883209,
0.011074194684624672,
0.022032929584383965,
0.08863983303308487,
-0.013262675143778324,
-0.037247877568006516,
-0.015268060378730297,
-0.018083481118083,
0.060820117592811584,
0.05398700758814812,
-0.00... |
<p>I am trying to learn the logistic regression model. I came to know that there is no linear relationship between predictor variables and response variables since response variables are binary (dichotomous). The link function used for logistic regression is logit which is given by
$$
\log \frac {p}{1 - p} = \beta X ... | g63023 | [
-0.010261990129947662,
-0.04103768989443779,
-0.0023966904263943434,
-0.020635616034269333,
0.03320463374257088,
-0.00194525474216789,
0.05279476195573807,
0.015438854694366455,
-0.05480434373021126,
-0.11348382383584976,
-0.04092279076576233,
0.04197627305984497,
0.02260114625096321,
-0.0... |
<p>I've got a (probably easy) question in how to handle empirical studies, when there are a lot of effects involved. I have a whole bunch of variables and I'd like to analyze just a few of them. But the problem is, that the model is wrong... So standard errors and coeficients itself are probably biased and so t-statist... | g63024 | [
-0.021300988271832466,
-0.024705544114112854,
-0.009032553061842918,
-0.009143242612481117,
0.03262851759791374,
-0.019312988966703415,
0.022752411663532257,
8.30727401535114e-7,
-0.02594085969030857,
0.0796671062707901,
-0.011002921499311924,
0.03447786346077919,
0.055581655353307724,
0.0... |
<p>I want to find correlation between job satisfaction (by likert-type questionare) and sex.</p>
<p>Should I use Kruskal-Wallis test to find correlation between two?</p> | g49659 | [
0.0065313223749399185,
0.0041043576784431934,
0.023677276447415352,
-0.04991086199879646,
-0.002623981796205044,
0.043719395995140076,
-0.018179161474108696,
-0.019445005804300308,
-0.01612675189971924,
-0.025600507855415344,
0.03070681355893612,
0.039743684232234955,
0.03091626800596714,
... |
<p>I calculate (with flow cytometry) pecentage of lymphocytes with a specific receptor (Lph*) as a ratio to general number of lymphocytes (Lph). Should I consider them (Lph*) as Poisson distributed?<br>
(My data set is <a href="http://stats.stackexchange.com/q/11887/5003">here</a>.)</p> | g45785 | [
0.00635656388476491,
-0.0042608315125107765,
-0.027120066806674004,
-0.0669972375035286,
0.048202451318502426,
-0.014641832560300827,
-0.026691200211644173,
0.0007724747993052006,
-0.00730780977755785,
0.019395772367715836,
-0.013287141919136047,
0.014772874303162098,
0.019742660224437714,
... |
<p>What is the additional coefficient 2 in AIC, or other deviance criteria? In the books or on the internet I keep reading "historical reasons". What the heck are those historical reasons? Is there a merit for the 2 keep appearing?</p>
<p><a href="http://en.wikipedia.org/wiki/Deviance_(statistics)" rel="nofollow">http... | g26192 | [
0.0206728707998991,
0.003409715835005045,
-0.021511025726795197,
-0.028187507763504982,
0.02482122927904129,
0.006644736044108868,
0.08929204940795898,
0.03637339919805527,
-0.03440142050385475,
0.009335966780781746,
-0.06009006127715111,
0.05359772592782974,
0.09164425730705261,
0.0314402... |
<p>I have data on damages on flowers from different treatments. The damage was originally count data (number of damages per flower) but the person collecting the data categorized the data in four levels - no damage (0) to a high damage level (3).</p>
<p>I know I could use logistic regression to model the odds but I wo... | g63025 | [
0.005127624608576298,
-0.06689070910215378,
-0.01117907464504242,
-0.048306286334991455,
0.00475391885265708,
-0.00790453888475895,
0.011430908925831318,
0.021702971309423447,
-0.032105956226587296,
-0.05092473700642586,
-0.022374052554368973,
0.04539841040968895,
0.006722222547978163,
-0.... |
<p>Do we assume that the population distributions are normal, or that the sample distributions are normal, or that the sampling distribution is normal? If the latter, what do we mean by sampling distribution in this context?</p>
<p>Why do we need to assume this?</p>
<p>Does the normality of these things entail or sug... | g49560 | [
0.037105806171894073,
0.0027425852604210377,
0.013737869448959827,
0.0064156814478337765,
0.011635269038379192,
0.051052119582891464,
-0.02208215743303299,
0.03516853228211403,
0.02821270376443863,
-0.019701296463608742,
0.0232020802795887,
-0.019651567563414574,
-0.024827687069773674,
0.0... |
<p><img src="http://i.stack.imgur.com/okkhr.png" alt="enter image description here">I found my four independent variables have a high positive association with my depepednet variable. However, except one independent variable, P value of all other indepdent variables are not significant in my regressino analysis. My hyp... | g63026 | [
0.03160163387656212,
-0.027037527412176132,
0.005536028183996677,
-0.013962236233055592,
0.021644804626703262,
0.004414099268615246,
-0.014623958617448807,
0.03139328956604004,
-0.04407778009772301,
-0.05922095477581024,
-0.006335369311273098,
0.007602117024362087,
-0.0739441066980362,
0.0... |
<p>Reading the Linear Mixed Model (LMM) literature I am aware that fitting a model using REML provides better estimates of variance parameters than fitting via ML. However, we should not compare nested models fitted with REML that have different fixed effects.</p>
<p>Recently, I have been fitting some models using GLS... | g63027 | [
0.05001220107078552,
-0.07304032146930695,
0.01111660711467266,
0.001107082120142877,
0.013418295420706272,
0.05648479238152504,
-0.006090668495744467,
0.0004301904991734773,
-0.038231171667575836,
-0.01359181571751833,
0.0035610462073236704,
-0.00748049421235919,
0.01621859520673752,
0.00... |
<p>I was told to come here by a friend to ask a stats question.</p>
<p>I took Social Stats and Methods of Social Research about 4 years ago and to be honest, I don't remember much about it. Now I'm writing a research paper and I can't find any basic tutorials to assist with a problem that would probably be pretty simp... | g63028 | [
0.018093286082148552,
-0.031880952417850494,
-0.013304241001605988,
-0.02587261237204075,
-0.05444178730249405,
-0.023771148175001144,
0.04508984088897705,
-0.015492628328502178,
0.0016203897539526224,
-0.06771975010633469,
0.023646831512451172,
-0.03782359138131142,
-0.023242998868227005,
... |
<p>I used <code>summary.formula</code> from <code>Hmisc</code> with continuous <code>Age</code> and binary outcome <code>O</code> with <code>test=TRUE</code>. This returned a p-value for <code>Age</code> predicting <code>O</code> (if I understand this correctly). </p>
<p>I then ran a <code>glm</code> using <code>Age<... | g20479 | [
0.016720768064260483,
0.03261245787143707,
-0.013756648637354374,
-0.03704504668712616,
0.006073611322790384,
-0.022244973108172417,
0.001016911817714572,
0.007216798607259989,
-0.038676824420690536,
-0.07157109677791595,
0.028771450743079185,
0.02597702667117119,
0.06250357627868652,
-0.0... |
<p>I have 2 distributions, 1 is, as far as im aware, normally distributed. Distribution 1 is the control group.</p>
<p>1st distribution</p>
<p>Mean = 0.000002757; Median = 0; StDev = 0.00119307; Number of data points = 91601</p>
<p>2nd distribution</p>
<p>Mean = 0.000058; Median = 0.000125; StDev = 0.001646243; Num... | g8109 | [
0.02819647453725338,
-0.030442729592323303,
-0.006256924010813236,
0.006083620246499777,
-0.01187889464199543,
-0.039992738515138626,
0.02794477343559265,
0.026982413604855537,
-0.017813626676797867,
-0.0054063573479652405,
-0.007425056304782629,
0.049617402255535126,
0.028810882940888405,
... |
<p>If the EACF of my TS suggests ARMA(0,0) and the Box-Ljung test does not suggest my TS has correlation, can I conclude that my TS is white noise or merely that there is no reason to suspect that it is not TS?</p>
<p>Conversely, if my TS is white noise, will I necessarily get ARMA(0,0) from EACF, ACF, PACF, etc?</p> | g63029 | [
0.04529888555407524,
-0.009100672788918018,
0.03062424808740616,
-0.08778323233127594,
0.04885289818048477,
-0.004331024829298258,
0.044742364436388016,
0.012134128250181675,
0.004562326241284609,
-0.03727254271507263,
-0.023369936272501945,
0.011396034620702267,
0.055390357971191406,
0.02... |
<p>I simulated a time series using expressions (3.10a), (3.10b) from (Hyndman et al., 2008). Next, I'd like to use a simple exponential smoothing method to forecast for the next period.
For a given initial point $\hat{y}_1$ I obtained the smoothing parameter $0<\alpha<2$, etc. </p>
<p>My question is as follows: ... | g20482 | [
0.019893895834684372,
-0.0382099375128746,
0.006677383556962013,
-0.042256247252225876,
-0.033560868352651596,
0.005328501109033823,
0.050135672092437744,
0.009946631267666817,
-0.03461821749806404,
-0.007071563974022865,
-0.008827333338558674,
0.0731787234544754,
0.08229155093431473,
0.00... |
<p>By default when we use a <code>glm</code> function in R, it uses the <a href="http://en.wikipedia.org/wiki/Iteratively_reweighted_least_squares" rel="nofollow">iteratively reweighted least squares</a> (IWLS) method to find the maximum likelihood estimation the parameters. Now I have two questions. </p>
<ol>
<li>Doe... | g63030 | [
0.03235577791929245,
-0.06351461261510849,
0.01746269129216671,
-0.003920788411051035,
0.031456202268600464,
0.009023690596222878,
0.0006249428843148053,
0.02359570376574993,
-0.0630769357085228,
0.012570476159453392,
-0.05898580327630043,
0.006401454098522663,
0.019903605803847313,
0.0360... |
<p>A probably very basic question about multi-factorial ANOVA. Assume a two-way design where we test both main effects A, B, and the interaction A:B. When testing the main effect for A with type I SS, the effect SS is calculated as the difference $RSS(1) - RSS(A)$, where $RSS(1)$ is the residual error sum of squares fo... | g8113 | [
-0.015803242102265358,
-0.027551688253879547,
0.0005000165547244251,
0.0006609272677451372,
-0.023139672353863716,
-0.051578931510448456,
0.038554828613996506,
-0.001805765787139535,
0.0018827980384230614,
-0.021826619282364845,
-0.025937970727682114,
0.03383967652916908,
0.05610191449522972... |
<p>I have a random field, F, defined on the surface of a sphere pixellized into about a million points. I know that F must consist of two components - F1 and F2, F1 being a true signal and F2 being some contaminant. They cannot be measured independently but it is known that they should be completely uncorrelated to eac... | g39684 | [
0.05588693544268608,
-0.06268277019262314,
-0.0010033865692093968,
-0.06754054874181747,
-0.011036274023354053,
0.010000384412705898,
0.04042438045144081,
0.013961449265480042,
0.023757698014378548,
-0.03638267517089844,
0.008561769500374794,
0.06354378908872604,
0.046522922813892365,
0.03... |
<h3>Context</h3>
<p>I have 25 men and 25 women as participants, and they did exactly the same thing: Each of them
heard an attractive dialogue and they had to choose between a photo of a
woman in red and a woman in green. Then each of them heard an unattractive
dialogue and they chose again between the red and the gre... | g63031 | [
0.001580800162628293,
-0.0011872417526319623,
-0.007123484741896391,
-0.07949113845825195,
0.02753913588821888,
0.03593834862112999,
-0.0024587290827184916,
-0.04277053102850914,
-0.011042099446058273,
-0.009882362559437752,
0.008718348108232021,
0.01546037569642067,
-0.0026425705291330814,
... |
<p>I have tried a number of different models to forecast the time series shown below, but so far I haven't found any models that satisfy me. I am looking for ideas for a suitable model. </p>
<p><img src="http://i.stack.imgur.com/KSvjl.png" alt="enter image description here"></p>
<p>The objective of the forecasting is... | g63032 | [
0.01016469020396471,
0.019397804513573647,
0.008552142418920994,
-0.05229204148054123,
-0.0211328212171793,
-0.09015852212905884,
0.0341101810336113,
-0.032928258180618286,
-0.04827389866113663,
-0.06139729917049408,
-0.01238185353577137,
0.07276324182748795,
0.06924161314964294,
-0.027291... |
<p>(Step 1) Using my predictive model, I predicted 1000 scores for my sample dataset. </p>
<p>(Step 2) I then calculate the random score using the same method for a randomized dataset. I firstly fit the distribution of the random score. </p>
<p>(Step 3) For each of my predictive score (1000 scores, in step 1), I ca... | g63033 | [
0.06329002976417542,
-0.015369954518973827,
0.0046319481916725636,
-0.03147643432021141,
0.020691798999905586,
-0.03390088677406311,
0.043279703706502914,
0.03875133767724037,
0.0015585323562845588,
-0.022132182493805885,
0.00597046222537756,
0.02946811355650425,
0.055549103766679764,
0.01... |
<p>I have a regression done on two groups of the sample based on a moderating variable (say gender). I'm doing a simple test for the moderating effect by checking whether the significance of the regression is lost on one set while remains in the other.</p>
<p>Q1: The above method is valid, isn't it?</p>
<p>Q2: The le... | g63034 | [
0.044616591185331345,
-0.014055751264095306,
0.021536681801080704,
-0.012019980698823929,
0.05559392645955086,
0.01024998165667057,
0.009862453676760197,
0.024775337427854538,
-0.06595712900161743,
0.0007671018829569221,
0.011781846173107624,
0.009170976467430592,
-0.01656753569841385,
0.0... |
<p>I would like to clarify how <a href="http://en.wikipedia.org/wiki/Granger_causality">the Granger causality</a> can/should be used in practice, and how to interpret the statistical significance given by the test.</p>
<p>Also, I would like to fill this table with things like "we don't know" or if we know something, w... | g39685 | [
0.0559522919356823,
0.004825158976018429,
-0.012353039346635342,
-0.02703377604484558,
0.052266672253608704,
-0.050559863448143005,
0.06750360131263733,
0.09758724272251129,
-0.020635779947042465,
-0.015847323462367058,
0.04560832679271698,
0.03908490389585495,
0.0546279139816761,
0.030101... |
<p>If you compare the standard errors of the OLS coefficients with the White correction, versus the ML estimates with the variance estimated with the sandwich estimator, which standard errors do you expect to be the biggest? And is it correct that both are robust to heteroscedasticity?</p> | g63035 | [
0.018336990848183632,
-0.03383168578147888,
0.01671893708407879,
-0.006909760180860758,
0.011443668976426125,
-0.02691415511071682,
0.013774552382528782,
0.02733701281249523,
-0.021369487047195435,
0.026705991476774216,
0.012537284754216671,
0.037602752447128296,
0.019716886803507805,
0.01... |
<p>I would like to propose a single model (decision tree), that is very variable, and validate it. I have choosen parameters after I had obtained good quality measures with a cross-validation.</p>
<p>I could build the model on the whole data set and show cross-validated measures. But I can't get a special graph (calle... | g20489 | [
-0.008411229588091373,
-0.020924685522913933,
0.0024207972455769777,
0.00455480208620429,
0.015277905389666557,
0.00003459478102740832,
-0.016794314607977867,
0.021811384707689285,
-0.01832197606563568,
0.002876689424738288,
-0.005402480252087116,
0.036675989627838135,
0.03195976838469505,
... |
<p>I have a question on the exponential distribution:</p>
<p><strong>Question</strong></p>
<blockquote>
<p>The waiting time to receive food after placing an order at the local sandwich shop follows an exponential distribution with a mean of 70 seconds. 80 percent of the patrons wait less than how many minutes to re... | g63036 | [
-0.011225924827158451,
0.06575378775596619,
0.00799231231212616,
-0.014882737770676613,
-0.0024876531679183245,
-0.03739314153790474,
-0.009589331224560738,
0.025191746652126312,
-0.03966113552451134,
0.033129774034023285,
-0.0027191380504518747,
0.035652995109558105,
0.01676424778997898,
... |
<p>Let's suppose that I'd like to apply dependent t-test to assess if there is a significant difference in the value of the dependent variable between a group of subjects $X_{1}$ and a related group of subjects $X_{2}$. </p>
<p>The same subjects are present in both $X_{1}$ and $X_{2}$. Now, the twist is that we have m... | g20493 | [
-0.020519694313406944,
-0.007594351656734943,
0.0012556134024634957,
-0.07651010900735855,
-0.037035439163446426,
-0.0380515418946743,
0.01768462359905243,
0.03407968208193779,
-0.08062076568603516,
0.022053297609090805,
0.06334478408098221,
0.03465251997113228,
-0.029330791905522346,
0.03... |
<p>While reading a few papers, I came across the term "gold set" or "gold standard". What I don't understand is what makes a dataset gold standard? Peer acceptance, citation count and if its the liberty of the researcher and the relevance to problem he is attacking?</p> | g20494 | [
0.04702275991439819,
0.07281631231307983,
-0.004850191995501518,
-0.07304417341947556,
0.043038733303546906,
0.03904999792575836,
-0.0000595667734160088,
0.021097367629408836,
-0.027246441692113876,
-0.02663431502878666,
0.008289366960525513,
0.005538535304367542,
0.01094353012740612,
-0.0... |
<p>I have data for a set of users (UID), over numerous dates (date), and over numerous sessions (these are just small chunks of time that a user was active) within each date. For each session I have a set of features (Xi) calculated in which I would like to estimate the gender of the user which is a binary variable (Y)... | g18081 | [
-0.0345076359808445,
-0.03611982986330986,
-0.003131853649392724,
-0.046402253210544586,
0.0031270929612219334,
0.010496844537556171,
0.05443549528717995,
-0.03985906392335892,
-0.08925758302211761,
0.0095894830301404,
-0.02610722929239273,
0.02919350005686283,
-0.0021684186067432165,
0.03... |
<p>Imagine the following simplified longitudinal data with 4 individuals and 3 variables (y1, y2, y3) measured at 50 occasions : </p>
<pre><code>dat<-data.frame(subject=as.factor(rep(1:4, each=50)),time=rep(1:50,4),y1=rnorm(200,50,20),y2=rnorm(200,70,20),y3=rnorm(200,20,20))
</code></pre>
<p>It is easy to plot at ... | g63037 | [
0.04411308467388153,
-0.0017864138353616,
-0.004934370983392,
-0.10298038274049759,
-0.00035014442983083427,
-0.054594993591308594,
0.0074517508037388325,
-0.07268919795751572,
-0.046522460877895355,
-0.04740563780069351,
0.013837913982570171,
0.07739769667387009,
0.01496409997344017,
0.01... |
<p>I posted this earlier in the week then retracted the question when I found a good source, not wanting to waste people's time. I haven't made much progress I'm afraid. In trying to be a good citizen here I will make the problem as clear as possible. I suspect there will be few takers.</p>
<p>I have a dataframe in R ... | g20498 | [
-0.012451140210032463,
-0.007576304487884045,
-0.016771875321865082,
-0.061598751693964005,
-0.0067776222713291645,
-0.030481481924653053,
0.06609483808279037,
0.013848218135535717,
-0.045022424310445786,
-0.06265637278556824,
-0.030000409111380577,
0.039289865642786026,
0.02257087081670761,... |
<p>Is there a specific method to detect change points(structural breaks) in a timeseries?(stocks prices)</p>
<p>Thanks</p> | g63038 | [
0.04962557554244995,
-0.007459430024027824,
-0.040470775216817856,
-0.06399055570363998,
0.02857377752661705,
-0.07910378277301788,
0.0013206026051193476,
-0.04020903259515762,
-0.024762049317359924,
0.050010327249765396,
0.006888780742883682,
0.02111881412565708,
-0.001437038998119533,
0.... |
<p>I am interested in applying a test of independence such as chi-square or log-likelihood in the case where the observations are not independent (observations are sequential in time and there is a temporal correlation). </p>
<p>I have read about computing the 'effective sample size' for use in variance estimates of d... | g39693 | [
-0.0008198307477869093,
0.03147859126329422,
0.014943888410925865,
-0.0326203815639019,
-0.06022065877914429,
-0.06492742896080017,
0.020101681351661682,
0.03579898923635483,
-0.01940353401005268,
0.013427476398646832,
0.02552803047001362,
0.01715855300426483,
0.0036633333656936884,
0.0292... |
<p>I'm trying to generate random textual data based on regular expressions. I'd like to be able to do this in R, as I know that R does have regex capabilities. Any leads?</p>
<p>This question has come up before in forums (<a href="http://stackoverflow.com/questions/274011/random-text-generator-based-on-regex">StackOve... | g46905 | [
0.012612562626600266,
-0.06776683777570724,
-0.005151619203388691,
-0.041645944118499756,
-0.03209592029452324,
-0.04605988785624504,
-0.01247724611312151,
0.051384638994932175,
0.005037198308855295,
-0.0718919187784195,
0.009042558260262012,
0.012102038599550724,
-0.017928970977663994,
-0... |
<p>I will simplify our problem in this way. Say there are 100,000 cases in total to examine. Due to the time limitation, we randomly selected 2,000 of them. Then we found 1,000 of them are invalid, so we have only 1,000 valid cases left. Finally we categorize these 1,000 valid cases into 2 categories, A and B; they hav... | g39696 | [
0.033692531287670135,
0.02207263559103012,
-0.025510987266898155,
0.022177156060934067,
-0.007415294647216797,
0.010903537273406982,
0.0038244626484811306,
0.021295785903930664,
0.01302072312682867,
0.010447513312101364,
0.02747245319187641,
0.00709302956238389,
0.05677707865834236,
0.0208... |
<p>QUESTION:</p>
<p>I have binary data on exam questions (correct/incorrect). Some individuals might have had prior access to a subset of questions and their correct answers. I don’t know who, how many, or which. If there were no cheating, suppose I would model the probability of a correct response for item $i$ as $lo... | g20502 | [
-0.019573375582695007,
-0.07158810645341873,
0.006767710205167532,
-0.01295718178153038,
-0.0011807995615527034,
0.009387164376676083,
0.08419090509414673,
-0.049771152436733246,
0.007593816611915827,
-0.04123417288064957,
-0.015368005260825157,
0.05616405978798866,
0.018744604662060738,
-... |
<p>I have 20 observations labeled for each class.
The number of classes is 5, so I have a total of 100 observations.
I want to classify one class vs. other classes (one vs. all). </p>
<p>For this, I first labeled '1' for one of five classes (= 20 observations), and '2' for the other classes (= 80 observations). Afte... | g63039 | [
-0.005090825259685516,
0.0044794543646276,
0.018254531547427177,
-0.10437145829200745,
0.03785126283764839,
-0.014407902956008911,
0.0576162189245224,
0.046136945486068726,
-0.035117752850055695,
-0.022598907351493835,
0.04108493775129318,
0.05657536908984184,
0.05453817918896675,
0.028758... |
<p>Apologies for newbie question but have failed to understand what I've read about in this area so pointers to the correct methods would focus my attention.</p>
<p>I have a piece of software which when tested repeatedly in the same way fails occasionally - say once in 20 runs.</p>
<p>If I make a change to fix the pr... | g63040 | [
0.023253168910741806,
-0.020291246473789215,
-0.012425733730196953,
0.020467134192585945,
-0.003015023423358798,
-0.034430623054504395,
0.03159865364432335,
0.029536744579672813,
-0.07299356907606125,
0.005873401649296284,
-0.04950607195496559,
0.04003254696726799,
-0.02819252386689186,
0.... |
<p>I have two sample data sets which are each a 1x95 vector containing the $\lambda$ of a Poisson. Each slot contains the $\lambda$ for the minute that the slot represents. So t1[1] is the starting lambda, t1[2] is the $\lambda$ after one minute, etc. The value of the lambda slowly decays over the time series. The seri... | g63041 | [
0.017795881256461143,
-0.03847140446305275,
-0.005474811885505915,
-0.06899309903383255,
-0.0012052349047735333,
-0.08186591416597366,
0.04689402133226395,
-0.06299876421689987,
-0.09580638259649277,
-0.04634292796254158,
-0.0278762336820364,
0.0791253000497818,
-0.013018789701163769,
0.00... |
<p>How conservative is Benjamini-Hochberg multiple testing correction relative to the total number of comparisons? For example, if I have a list of 18,000 features for two groups and I perform a Wilcoxon test to get a p-value. I adjust that p-value using Benjamini-Hochberg and next to nothing comes out as significant. ... | g20506 | [
0.01851884461939335,
-0.027876822277903557,
-0.002242959337309003,
0.040957607328891754,
0.026127945631742477,
-0.030674828216433525,
0.05848081037402153,
0.06993860751390457,
-0.05312320217490196,
-0.007665121927857399,
0.01618795096874237,
0.006935031618922949,
-0.0018677768530324101,
0.... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.