question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I have a bunch of articles presenting "OR" with a- 95% CI (confidence intervals).</p>
<p>I want to estimate from the articles the P value for the observed OR. For that, I need an assumption regarding the OR distribution. What distribution can I safely assume/use?</p> | g59791 | [
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<p>OpenCV provides an implementation of random forest named random trees and derived from a decision tree class. One parameter to train the random forest is the maximum depth, which in the provided examples is typically between 10 and 20. I learned that random forest is generally grown to its full depth and no pruning ... | g59792 | [
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<p>I'm working on a data set and linear regression is beating a randomforest (the metric is weighted mean absolute error - I have a list of weights and each difference $|\text{predicted} - \text{actual}|$ is multiplied by that rows weight (which is a $\sqrt{\text{time}}$ so longer time between observations are charged ... | g45151 | [
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<p>Suppose i have a little over 20.000 monthly time series spanning from Jan'05 to Dec'11.
Each of these representing global sales data for a different product. What if, instead of computing forecasts for each and every one of them, I wanted to focus only on a small number of products that "actually matter"?</p>
<p>I ... | g861 | [
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<p>Assume ${{X}_{1}}$, ${{X}_{2}}$, ${{X}_{3}}$,...,${{X}_{n}}$ are i.i.d. samples from distribution with density f, and cdf F.</p>
<p>Let V=min( ${{X}_{1}}$, ${{X}_{2}}$, ${{X}_{3}}$,...,${{X}_{n}}$)</p>
<p>To find the minimum $${B}_{v}={\{V\ge{v}\}}=\{{X}_{1}\ge{v}\}\cap\{{X}_{2}\ge{v}\}\cap...\cap\{{X}_{n}\ge{v}\... | g49706 | [
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<p>Young children were given a questionnaire before and after a presentation. There were 6 questions to answer yes or no. I would like to find out if there is a significant difference between the questionnaires taken before and after the presentation. </p>
<p>I could score each test and do repeated measures testing... | g59793 | [
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<p>I find it hard to understand what really is the issue with <em>multiple comparisons</em>. With a simple analogy, it is said that a person who will make many decisions will make many mistakes. So very conservative precaution is applied, like Bonferroni correction, so as to make the probability that, this person will... | g59794 | [
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<p>I am trying to build a time series regression forecasting model for an outcome variable, in dollar amount, in terms of other predictors/input variables and autocorrelated errors. This kind of model is also called dynamic regression model. I need to learn how to identify transfer functions for each predictor and wo... | g59795 | [
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<p>In my data, I have a class variable, denoted as $C$. This class variable values are ${0, 1}$ (binary). Almost all observations of $C$ are 0 (close to 100%, more precisely, 97%). I would like a "performance" test on different classification models (it could be accuracy). What I am afraid of happening is that if I hav... | g59796 | [
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<p>Do you ever center AND standardize variables in multiple regression? It seems as if standardization would automatically center variables...is this true?</p> | g59797 | [
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<p>I have implemented a genetic algorithm for a fuzzy c-means clustering in Matlab. Its performance should be apriori better than that of the classic fuzzy c-means (fcm function in matlab). However, on all the classical datasets I am comparing them, both algorithms converge to the same value of the objective function.<... | g15558 | [
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<p>I would like to perform wavelet smoothing at different scales in R. I got the idea from this figure (panel A) were they measure the density/intensity of a particular signal at different scales.</p>
<p>Here the image shows the linear coordinates along one chromosome on the x axis and the y axis shows the 'bandwidth'... | g15559 | [
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<p>This CrossValidated post on <a href="http://stats.stackexchange.com/questions/7343/how-to-correct-uneven-sampling-distribution-when-calculating-the-mean">estimating mean from uneven samples</a> suggests using a (any) Riemann Sum to estimate the integral of an unevenly sampled 1D function. </p>
<p>To me the obvious... | g59798 | [
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<p>How do I assess what Pareto (or similar) function/distribution is most appropriate for fitting my data?</p>
<p>I want to be able to model a dataset with a distribution of many-small, few-large that looks very similar to a Pareto distribution, but I do not have the statistics background to evaluate what model is mos... | g15563 | [
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<p>i'm trying to understand how MCMC works. In my special case I have to stochastic processes which are superposed. I observe data $Y=\{Y_1,...Y_T\}$ and assume, that there are some latent variables $A_t$ and $B_t$ such that $Y_t = A_t + B_t$ for all $t$.</p>
<p>Now, $A$ is generated by an Ornstein Uhlenbeck Process w... | g15564 | [
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<p>I have a set of paired data that I am using to calculate a ratio. The ratio is calculated as the sum of column 2 over the sum of column 1 (please see below)</p>
<pre><code>Col1 Col2
3744519.37 0
2739505.37 0
46378122.62 0
2887639.57 78652.84
6000000 0
971112.48 0
7815969.01 0
11920577.36 0
2060120.66 0
4... | g15565 | [
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<p>We are currently analyzing experimental data with the following format:</p>
<p>All participants (n=100) make repeated allocation decisions in fixed intervals: 100% is divided up into two allocation options at each step, therefore the dependent variable can be treated as a proportion. For each participant we therefo... | g59799 | [
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<p>I am conducting research in which employee engagement will be evaluated on approximately 20 participants. They will complete an 11 question Likert-scale survey, have interventions done on them (read a book, read 3 articles, and sit through a lecture), and complete the same 11 question survey. Is the correlated t-te... | g59800 | [
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<p>Is there a free alternative available for the Stata procedure <a href="http://www.stata.com/manuals13/mimiimputeintreg.pdf" rel="nofollow">mi impute intreg</a> (Impute using interval regression)? For example as an R package. I have not found any yet.</p> | g59801 | [
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<p>I am fairly new in the area of text mining and want to practice my skills a little. I have the following task at hand which I want to work on. I have a large list of short texts (~100.000) and every text has on average 3 tags / labels assigned to it. What I want now is train a predictive model, with which I can assi... | g59802 | [
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<p>I'am working on a glm model (family:normal, link:identity) using complex survey design (package: survey), My interest is to evaluate the effect of the variable DLA on the scores.</p>
<p>I ran the model 1 considering DLA as categorical (tertiles):</p>
<pre><code>model1=svyglm(score~DLA_tert+race+pir_4+age_yr+as.fac... | g59803 | [
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<p>There are several math-heavy papers that describe the Bayesian Lasso, but I want tested, correct JAGS code that I can use.</p>
<p>Could someone post sample BUGS / JAGS code that implements regularized logistic regression? Any scheme (L1, L2, Elasticnet) would be great, but Lasso is preferred. I also wonder if there... | g59804 | [
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<p>I have lately been reading papers regarding Sentiment Analysis, where most researches report that their improvements made them achieve an increase of 1~2%, or even 0.5% in accuracy compared to baseline (non-trivial) methods. </p>
<p>Of course, I understand that such an increase (even if small, if statistically si... | g59805 | [
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<p>I am working on my master thesis at the moment and planned on running the statistics with SigmaPlot. However, after spending some time with my data I came to the conclusion that SigmaPlot might not be fit for my problem (I may be mistaken) so I started my first attempts in R, which did not exactly make it easier.</p... | g278 | [
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<p>Say I have an <strong>observed</strong> data set ($n_i$) and I want to obtain the best fit out of 10 data sets produced by a <strong>model</strong> dependent on a single parameter $a$ ($m_i(a)\;a=1..10$).</p>
<p>Suppose I use a Poisson likelihood distribution:</p>
<p>$P_i(a)=\frac{m_i(a)^{n_i}}{e^{m_i(a)}n_i!}\; ... | g44903 | [
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<p>I have run </p>
<pre><code> 'fitdistr(mydata, "Gaussian")'
</code></pre>
<p>and get the following error message:</p>
<pre><code>Error in optim(x = c(34.513, 25.587, 18.251, 52.836, 38.206, 42.395, 47.22, :
initial value in 'vmmin' is not finite
</code></pre>
<p>However when I run </p>
<pre><code> 'fitdist... | g59806 | [
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-... |
<p>I have two probabilities $p$ and $q$. $p>q$, and they aren't correlated. I'm going to calculate $i$ such that $p^i=q$, which is easily done as $\log_p(q)$.</p>
<p>Now, I'd like to also calculate a confidence interval for $i$, which is necessarily going to be a function of both $p$ and $q$'s confidence intervals.... | g59807 | [
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<p>I have aggregated death counts and some categorical predictors e.g. era, drug use, and I'm running a Poisson GZLM in SPSS, also a <code>glm</code> in Stata (generalized linear model). There are many, but not excessive, zeros and it has been suggested to me to add 0.5 to the observed values. When I do that the GENLIN... | g59808 | [
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<p>I have an idea about producing a genetic algorithm. But it involves using a relationship which believe could be defined as a horizontal Asymptote. I have found an image that depicts the type of relationship I will attempt to apply. However finding out what it is called and what the standard equation is that defines ... | g59809 | [
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<p>I am trying to use <a href="http://en.wikipedia.org/wiki/Broyden%E2%80%93Fletcher%E2%80%93Goldfarb%E2%80%93Shanno_algorithm" rel="nofollow">bfgs</a> algorithm in order to fit a set of $\{(x,y),f(x,y)\}$ to a function in the form of let's say $a\cdot cos(x)+b \cdot y=f(x,y)$.</p>
<p>I try to understand how to use bf... | g15570 | [
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<p>I am fitting a gam model in R (using the <code>gam</code> function in <code>mgcv</code>) to account for some non-linear effects in my data. A stripped down example of what I am doing in R is:</p>
<pre><code>mod=gam(y~s(x)+s(z),data=df)
</code></pre>
<p>However, I want to add a slightly more complicated variance mo... | g59810 | [
0.0037557606119662523,
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<p>When using the persistent CD learning algorithm for Restricted Bolzmann Machines, we start our Gibbs sampling chain in the first iteration at a data point, but contrary to normal CD, in following iterations we don't start over our chain. Instead we start where the Gibbs sampling chain in the previous iteration ended... | g59811 | [
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<p>Recently, I built a classification model based on the imbalanced data set(positive sample is minority and negative sample is majority), and the model gave the following result for the test set: </p>
<blockquote>
<p>True Positives = 0</p>
<p>True Negatives = 139</p>
<p>False Positives = 0</p>
<p>Fal... | g15574 | [
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0.0... |
<p>You can further improve a linear mixed model with random intercept and slope by specifying a structure in the residuals (for example AR(1)).</p>
<p>In SAS it is possible, but I hope this is also already possible in R. Does somebody knows how to do this?</p>
<p>I am using both packages lme4 and nlme.</p>
<p>Thank ... | g480 | [
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<p>I am fairly new to Stata, currently taking an undergrad time series econometric class. The economic significance of the regression I am running and attempting to forecast is all but zero; this is simply my learning how to use Stata somewhat efficiently. I have run an Autoregressive Distributed Lag (ADL) regression o... | g59812 | [
0.03844756633043289,
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0.001... |
<p>In an aligned rank transform preceding a two-way ANOVA, the procedure is:</p>
<ul>
<li>save residuals by performing a standard ANOVA </li>
<li>use Aggregate to determine effects for group means (mij for interaction, ai as first factor, bj for second factor) </li>
<li>eliminate interaction effect from residual to de... | g59813 | [
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0.03986930847167969,
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0.0... |
<p>The problem gives 50 observations and then asks to check whether the data comes from a normal distribution. </p>
<p>For instance if these are your observations then how would you go about testing to see if they come from a normal distribution.</p>
<pre><code>−1.28 −1.22 −0.45 −0.35 0.72
−0.32 −0.80 −1.66 1.39 0.38... | g59814 | [
0.0201009102165699,
-0.023191625252366066,
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0.06722475588321686,
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0.027938295155763626,
0.03175985440611839,
-0.0... |
<p>I want to decide the capacity $C$ of a table so that it has residual odds less than $2^{-p}$ to overflow for given $p\in[40\dots 120]$, assuming the number of entries follows a Poisson law with a given expectancy $E\in[10^3\dots 10^{12}]$.</p>
<p>Ideally, I want the lowest integer <code>C</code> such that <code>1-C... | g15577 | [
0.030134158208966255,
0.010937334969639778,
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... |
<p>A common rule of thumb in social science is to have at least $30$ observations for regression (without any complicated effects). Does someone know such rule of thumb for GAMs? Are $50$ observations enough for a simple additive model with two parametric terms and two smoothers?</p> | g59815 | [
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<p>I have an ecological data set, whereby sediment mud content (%) (i.e. the continuous explanatory variable) is thought to be explaining the spatial distribution (i.e. presence/absence) of various estuarine benthic macroinvertebrate taxa (i.e. the binary response variable). Below is a subset of the data (actual data c... | g59816 | [
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0.0041303... |
<p>The definition of a <em>log-normal distribution</em> of a random variable is based on normality of its logarithm. I'm curious whether there exist a <em>specific term</em> for cases, where <em>log-transformed data</em> does not conform to a normal distribution, but to a <em>mixture distribution</em>. Moreover, I woul... | g59817 | [
0.018007874488830566,
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... |
<p>To find association between peer's support (independent variable) and work satisfaction (dependent variable) I wish to apply chi-square test. Peer's support is categories in four groups according to the extent of support: 1=very less extent, 2=to some extent, 3=to great extent and 4=to very great extent. Work satisf... | g49485 | [
0.011186362244188786,
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0.0... |
<p>Assume a data set with multiple columns, where the categorical data are coded. What is the best rule(s) or rule of thumb to determine whether each column contains qualitative data or quantitative data?</p>
<p>One possible way is to count the number of unique values and if the unique value count is less than some th... | g49571 | [
0.01255615521222353,
0.05055544897913933,
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0.0022861550096422434,
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0.012172825634479523,
0.06013397127389908,
0.04... |
<p>Lets say I have two time series a and b and I predict the next value and a prediction interval (say lower and upper 80%) of each of these two. I end up with something like that: a: [10, 20, 30] and b: [2, 7, 12] (as [lo80%, prediction, high80%]). As these time series are independent, I see I could just add 20 + 7 to... | g15581 | [
0.005733044818043709,
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0.0022578174248337746,
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0.07634437829256058,
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... |
<p>Suppose we have count data. It seems that a generalized ARMA model would be good to use. In Rm these is function:</p>
<blockquote>
<p>garma(link = c("identity", "loge", "reciprocal",
"logit", "probit", "cloglog", "cauchit"),
earg=list(),
p.ar.lag = 1, q.lag.ma = 0,
coefsta... | g59818 | [
0.009121295996010303,
0.021750040352344513,
0.004993918817490339,
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0.017688196152448654,
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0.018260346725583076,
0.01011442020535469,
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0.0011330515844747424,
0.00782306119799614,
0.012533108703792095,
0.05560240522027016,
0.008... |
<p>I do not know a lot about stats so forgive me. I have a dataset which has $N$ number of participants and their choice between 1, 2, and 3 at any given point. I want to analyze the distribution of the choices between 1, 2, and 3 by participants' age and sex. How would I set up a test to look for significant intera... | g15583 | [
-0.025573106482625008,
0.029950030148029327,
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0.020171161741018295,
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0.01680724136531353,
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0.012069820426404476,
0.014853397384285927,
... |
<p>I want to perform k-means clustering on some objects I have, but the objects aren't described by "points". However, I am able to compute the distance between any two objects (it is based on a similarity function). I've implemented K-means before, but it's not clear to me how to update the clusters to be the cluste... | g59819 | [
-0.02966637909412384,
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0.021344920620322227,
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-0.004320325795561075,
-0.000019353965399204753,
0.03799411281943321,
0.12924790382385254,
... |
<p>Suppose we have some house price data for 30 years (1970-1999). This is yearly data (30 data points). Suppose some major event $X$ happened on 1980. I want to see whether this event affected prices later on. Is using median filters a good methodology for detecting outliers in later years?</p> | g59820 | [
0.04602434113621712,
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0.008912036195397377,
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-0.030936531722545624,
0.043510228395462036,
0.051246389746665955,
0.0134110227227211,
0.03... |
<p>I am considering the following question: when there are ties, how are ranks calculated?</p>
<p>In some references, they first rank them without repeating the ranks, and then average the ranks of those ties and assign the average rank to each one in the ties.
I was wondering if that way is unanimously used in statis... | g37554 | [
0.020925335586071014,
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0.012407349422574043,
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0.02215241640806198,
0... |
<p>I am starting to work in R with the following case: 35 countries have scores between [0,1] in 120 dimensions and I need to show that there are differences in the way their scores distribute across these dimensions. For example, if there were 5 dimensions, (1,0.5,0,0,0) is different than (0,0,0,0.5,1). This is why I ... | g29587 | [
0.05376027151942253,
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0.01929350569844246,
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0.04808293282985687,
0.00... |
<p>I have a data set that lists every country in Africa, what their main contribution is to their GNI (industry,agriculture, etc), their GNI, and whether or not they have access to the sea. I need to find the relation between having access to the sea and GNI, and then what kind of economy they have an GNI (separately).... | g49572 | [
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0.01047823578119278,
-0.0145... |
<p>I have the following passage from a set of lecture notes I am working on that I would like to understand a little better.</p>
<p>$\underline{\text{Algorithm for Rejection Sampling}}$:</p>
<p>Given two densities $f$, $g$, with $f(x) < M.g(x)$ for all $x$, and some constant $M$, we can generate a sample from $f$ ... | g59821 | [
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<p>From <a href="http://en.wikipedia.org/wiki/Wilcoxon_signed-rank_test" rel="nofollow">Wikipedia</a></p>
<blockquote>
<p>Calculate the test statistic $W$ $$
W = \left|\sum_{i=1}^{N_r} [\operatorname{sgn}(x_{2,i} - x_{1,i}) \cdot R_i]\right|, $$the absolute value of the sum of the signed ranks.</p>
<p>As $... | g44934 | [
0.007325983140617609,
0.02961554005742073,
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0.03618177771568298,
0.010065499693155289,
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0.06085261330008507,
0.011694732122123241,
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-0.010839360766112804,
-0.06886469572782516,
0.06839169561862946,
-0.013556628488004208,
0.04... |
<p>I'm on a time series project for an undergraduate course. For the project I'm trying to come up with an ARIMA model for the housing starts data set.
<a href="http://www.quandl.com/FRED/HOUST-Housing-Starts-Total-New-Privately-Owned-Housing-Units-Started" rel="nofollow">http://www.quandl.com/FRED/HOUST-Housing-Start... | g15508 | [
0.0007607898442074656,
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0.022036662325263023,
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0.01938670687377453,
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0.07099378854036331,
0.023696886375546455,
0.06494813412427902,
0.058601975440979004,
-0... |
<p>Do machine learning algorithms like Boosted Regression Trees (in the R package (gbm)) follow the same statistical assumptions of not including correlated predictor variables in GLM? </p>
<p>i.e. If I have two correlated predictrs (rsq=.7) should I be including both into my BRT model? </p>
<p>Any input or thoughts ... | g44942 | [
0.05880894511938095,
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0.015651529654860497,
0.022923029959201813,
0.01975046843290329,
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0.03212625905871391,
0.05519714206457138,
0.026925716549158096,
0.026... |
<p>Is there a commonly used name for a function that maps time slices in a day to probability of a specific event happening in that slice? I was using probability distribution but I guess since the total of y values can be as large as the number of time slices (i.e., this event happens at every time slice) this is misu... | g59822 | [
0.023473335430026054,
0.02196587435901165,
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0.014902755618095398,
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0.034105271100997925,
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0.08570941537618637,
0.045... |
<p>I've got a tricky document classification question. Each document in my collection can be assigned a label. In my training set the average is about 3 different labels assigned to each document. What I have learned in the training set is $P(\text{label}|\text{doc_word})$ for many label/doc_word pairs. I want to c... | g59823 | [
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0.028119878843426704,
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0.000012912395504827145,
0.00033763141254894435,
0.030612753704190254,
0.01842069253325462... |
<p>Let $(X, Y)$ have a normal distribution with mean $(\mu_X, \mu_Y)$, variance $(\sigma_X^2, \sigma_Y^2)$ and correlation $\rho$. I want to know the corresponding marginal densities.</p>
<p>All I found so far was the well-known density expressions for $X\sim N(\mu_X, \sigma_X^2)$ and $Y\sim N(\mu_Y, \sigma_Y^2)$, but... | g44945 | [
0.038219522684812546,
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0.008748707361519337,
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0.01992824114859104,
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0.034300707280635834,
-0.020965319126844406,... |
<p>Let $(X,Y)$ be chosen uniformly on the triangle $\{(x,y)\in\mathbb R^2:x+y\leq1,x\geq0,y\geq0\}$. What is the density function of $(X,Y)$? Find the distributions of $X+Y$, $X-Y$,$XY$.</p>
<p>What I've tried: </p>
<p>$\displaystyle \frac{1}{Area\hspace{1mm} of\hspace{1mm} Triangle} =\frac{1}{\frac{1}{2}\cdot 1 \cdo... | g59824 | [
0.039786700159311295,
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0.02942408248782158,
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0.010772542096674442,
0.0587480254471302,
-0.02... |
<p>Do you just report that MANOVA significance test is significant, or do you have to include contrast estimates (SPSS <code>K MATRIX</code>)? In the latter case, what are recommended formatting guidelines?</p> | g15591 | [
0.002254741033539176,
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0.001984129659831524,
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0.06915519386529922,
... |
<p>I need to do a seemingly unrelated regression of a non-linear model. Can't figure out how to do it in Stata.</p>
<p>Any advice much appreciated.</p>
<p>Thanks,
Ben</p> | g59825 | [
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-0.009743979200720787,
-0.012565679848194122,
0.03414629399776459,
0.0448276661336422,
... |
<p>I have $(x,\ y)$ pairs with a strongly suspected linear correlation. So I want to fit the "best" linear function in order to make predictions for unknown $x$'s. These pairs don't represent a function, i.e. there are many different values of $y$ for some $x$. I want to know if there is an issue with that considering ... | g59826 | [
0.009669939056038857,
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<p>I have very big data and low number of observations. So I decided to use PCA to reduce dimension of the data. The following is R example (just an dummy example - for workout):</p>
<pre><code>xmat <- matrix(sample(-1:1, 100000, replace = TRUE), ncol = 1000)
colnames(xmat) <- paste ("V", 1:1000, sep ="")
rownam... | g15595 | [
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0.03914310410618782,
0.03270132839679718,
0.04204699397087097,
0.01... |
<p>What is the distribution of a normally distributed random variable $X^2$ with $X\sim N(0,\sigma^2/4)$. I know $\chi^2(1)=Z^2$ is a valid argument for when squaring a <strong>standard normal</strong> distribution, but in the case of non-unity variance?</p> | g59827 | [
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<p>I have done a multiple regression analysis of a group of design variables for a system I am analyzing. From this I determined the standardized regression coefficients. All of the variables fall into one of two groups, architectural variables and control variables. I would like to determine the relative importance... | g59828 | [
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<p>The total sum of squares is expressed as below [1][2],</p>
<p>\begin{align}
\rm{TSS} &= MSS + ESS
\end{align}</p>
<p>\begin{align}
\sum_{i=1}^n (y_{i}-\overline{y})^2 &= \sum_{i=1}^n (\hat{y}_{i}-\overline{y})^2 + \sum_{i=1}^n (y_{i}-\hat{y}_{i})^2
\end{align}</p>
<p>I have a set of exponentially distrib... | g59829 | [
0.024878405034542084,
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<p>When a univariate Gaussian distribution has known variance and unknown mean, its canonical link function is identity. So its generalized linear model under the canonical link function is simply $E(Y|X) = X^T \beta$.</p>
<p>When a univariate Gaussian distribution has both mean and variance unknown, </p>
<ul>
<li><p... | g15598 | [
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<p>Suppose you observe $\left(x_i,y_i\right)$, where $y_i \sim \mathcal{N}\left(\mu_i,\sigma_i^2\right)$. There are a number of ways that the $\mu_i, \sigma_i$ might vary with $x_i$:</p>
<ol>
<li>If one suspected $\mu_i$ varied with $x_i$, but $\sigma_i$ is independent of $x_i$, one could perform plain old linear regr... | g59830 | [
0.000892121228389442,
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0.06362130492925644,
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<p>If you are given the parameter estimates and their p value and ACF PACF only how to can you chose the most suitable model if there are more than one model where parameters are significant? </p> | g59831 | [
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<p>I'm working on a classification problem and I have a very high F1 baseline of 85%. I have trained three classification models and I want to know which one is the best. How can I do so? </p>
<p>I tried two ways:</p>
<ol>
<li><p>To compare each model against the baseline using paired t-test. So I have tests like: </... | g49304 | [
0.003790933871641755,
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<p>I have two groups of data. Each with a different distribution of multiple variables. I'm trying to determine if these two groups' distributions are different in a statistically significant way. I have the data in both raw form and binned up in easier to deal with discrete categories with frequency counts in each.... | g59832 | [
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<p>I'm interested in why dependent observations are a problem in statistics. Let's say you want to know if there is a difference in mean exam scores between two schools. You collect 50 observations in each school. These 50 observations are derived from 5 different classrooms in each school and there is dependence withi... | g59833 | [
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<p>I had an intervention with control group and experimental group. Both groups had pre- and post-tests. So I was using 4 graphs to explain in a presentation. (pre-test control, pre-test experiment & post-test control and post-test experiment) Each graph showed responses to a likert scale question with 5 options. <... | g15514 | [
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<p><em>I am doing my thesis and have absolutely no previous experience in statistics.</em> </p>
<p>I have constructed several Likert scales by forming composites scores each based on 4-6 items which tests the level of agreement of my respondents. </p>
<p>Specifically, I have created two scales 'purchase behaviour' a... | g59834 | [
0.01666281372308731,
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0.0022592933382838964,
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0.024056946858763695,
0.01920287124812603,
0.0023... |
<p>This is a question that's been bugging me for some time. The problem is this: I'm modelling the residuals of a model $f(t,\vec{\theta})$ with (what I think is) an AR process plus a white noise process via MCMC using a multivariate gaussian likelihood, where I model the covariance matrix elements equal to the element... | g15604 | [
0.0421491377055645,
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0.0014457360375672579,
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0.005216113291680813,
0.04916372522711754,
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0.06198030337691307,
0.0044565349817276,
0.013053861446678638,
0.044164545834064484,
0.011... |
<p>I would like to test several (multivariate --between 5 and 20 dimensions) depth measures empirically. I'm looking for a couple of test-benches (read distributions). These should be:</p>
<ol>
<li>non-elliptical, </li>
<li>absolutely continuous,</li>
<li>uni-modal </li>
<li>have convex contours (if you prefer, level ... | g37661 | [
-0.005216550547629595,
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0.029317541047930717,
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0.0022834246046841145,
0.0025263666175305843,
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-0.00026836420875042677... |
<p>I am currently reading "Bayesian Data Analysis" by Gelman et al. and my main goal was to learn about Hierarchical modelling on chapter 5. I read until chapter 4 and the book is written terribly for a taste of a math student as it is pretty sketchy and engineering oriented. </p>
<p>I decided to not to continue anymo... | g59835 | [
0.05913645029067993,
0.03041023388504982,
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0.005715723615139723,
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0.017740735784173012,
0.07409101724624634,
... |
<p>Kalman filter can accommodate time varying system matrices. Equations to run the filter are the same and it preserves its optimality under linear gaussian model. </p>
<p>My question is the following:</p>
<p>Can the evolution of time varying system matrices be stochastic? In some references I seem to read between t... | g254 | [
-0.00030843279091641307,
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0.010504079051315784,
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0.016485337167978287,
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0.04006034508347511,
0.02258022502064705,... |
<p>In the following code I perform a logistic regression on grouped data using glm and "by hand" using mle2. Why does the logLik function in R give me a log likelihood logLik(fit.glm)=-2.336 that is different than the one logLik(fit.ml)=-5.514 I get by hand? </p>
<pre><code>library(bbmle)
#successes in first column, ... | g15518 | [
0.0076748584397137165,
-0.05642358586192131,
0.005238635465502739,
-0.025498492643237114,
0.0020464842673391104,
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0.05836114287376404,
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-0.032754138112068176,
-0.009790707379579544,
0.01689687930047512,
0.04624509438872337,
... |
<p>I have a random intercept logistic regression (due to repeated measurements) and I would like to do some diagnostics, specifically concerning outliers and influential observations. </p>
<p>I looked at residuals to see if there are observations that stand out. But I would also like to look at something like Cook's d... | g59836 | [
0.020448502153158188,
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0.06144777685403824,
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0.03581247106194496,
0.0... |
<p>I am using R with package <code>tree</code> to build a classification tree to summarize and represent my data. I have only 27 records and 10 variables. I built the tree but the but the <code>xerror</code> grows:</p>
<pre><code> CP nsplit rel error xerror xstd
1 0.2 0 1 1.0 0.40369
2 0.0... | g59837 | [
0.01977185346186161,
0.010350290685892105,
-0.02139311470091343,
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0.0005497771198861301,
0.01066272146999836,
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0... |
<p>I am currently trying to find the best way to analyse my data.</p>
<p>Participants were tested longitudinally on up to five occasions. On each day participants were assessed for the presence or absence of a neurological marker (dichotomous), and were tested on a continuous measure (scoring 0-10). I simply want to c... | g28260 | [
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0.005304296500980854,
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-0.012877173721790314,
0.010942676104605198,
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-0.0130648771300911... |
<p>I have a binary classification problem.
My inputs consist of a time-series of values plus some binary values.
For real-valued inputs I would usually use a neural network, while for binary-values inputs I would use either a neural network with a step function or some other method fit for binary inputs (like a maximu... | g59838 | [
0.03174898400902748,
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0.025056343525648117,
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0.0013906072126701474,
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0.033494267612695694,
0.05439167469739914,
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-0.017393823713064194,
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0.004598874598741531,
0.04705829545855522,
0.0... |
<p>I need to perform survival analysis for 4 different groups in a study. When I use the Logrank test, the null hypothesis is rejected.</p>
<p>My question is, how can I tell now exactly which pair of groups causes the null hypothesis to be rejected? Is there a special post-hoc test, or should I repeat the logrank test... | g59839 | [
0.005276492331176996,
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0.050766266882419586,
0.005358721129596233,... |
<p>My question follows from a previous excellent response in another post:</p>
<p><a href="http://stats.stackexchange.com/questions/14004/intra-and-inter-rater-reliability-on-the-same-data">Intra- and inter-rater reliability on the same data</a></p>
<p>Wow, what a truly great response! I am running through a similar ... | g44960 | [
-0.01665409840643406,
0.005843007937073708,
0.0029748096130788326,
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0.02780308574438095,
0.04637623205780983,
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-... |
<p>What is the best way to test for difference of proportions when of them is 0% (or 100%) ?</p>
<p>edit: I have two raters, who give a score of either 1 or 0. One of them gave a 0 in every single case. Now I want to know if the proportions of 1's is significantly different between the two.</p> | g59840 | [
0.048422399908304214,
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0.06059934198856354,
0.0012893264647573233,
0.009825987741351128,
-0... |
<p>I have a function which simulates the outcome of a particular card game, and returns a value denoting the outcome of the game. I want a concise syntax for sampling multiple plays of the game, and getting a vector containing the outcomes. This is what I want to be able to write:</p>
<pre><code>sample(cardgame(params... | g15614 | [
0.008010399527847767,
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-0.014923921786248684,
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-0.049634043127298355,
0.03591078147292137,
0.0... |
<p>I use LMM to analyse my data and my variables are as follows:
DV: continuous
IV: 1) color(red, blue, green), height(low, tall, medium), and sex (male, female)</p>
<p>Then for color, "red" is baseline, and for height, "low" is baseline.</p>
<p>The output is like this:</p>
<pre><code>colorblue (sig)
colorgreen
heig... | g59841 | [
0.04296879097819328,
-0.037126585841178894,
0.010500282049179077,
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0.035530734807252884,
0.0066276839934289455,
0.05827212706208229,
0.011433769948780537,
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-0.01217931043356657,
-0.019436607137322426,
0.05155746266245842,
-0.01005121972411871,
0.04... |
<p>If you choose to analyse a pre-post treatment-control design with a continuous dependent variable using a mixed ANOVA, there are various ways of quantifying the effect of being in the treatment group.
The interaction effect is one main option.</p>
<p>In general, I particularly like Cohen's d type measures (i.e., ${... | g44970 | [
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0.02231278456747532,
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0.... |
<p>There is an experiment in which biological samples are taken for several treatments and a control. For each treatment, we have enough resources to evaluate 5 samples.</p>
<p>Some researchers suggest (for technical reasons) that for each treatment, we should collect ten samples and pool them, such that we have five ... | g15619 | [
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-0.02543889544904232,
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0.014000536873936653,
0.018087925389409065,
... |
<p>What is the <a href="http://en.wikipedia.org/wiki/VC_dimension" rel="nofollow">VC dimension</a> of <a href="http://en.wikipedia.org/wiki/Support_vector_machine" rel="nofollow">SVM</a> with the polynomial kernel $k(x,x')=(1+<x,x'>_{\mathbb{R^{2}}})^{2}$ for binary classification in $\mathbb{R^{2}}$?</p>... | g45704 | [
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0.020466327667236328,
0.028638606891036034,
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0... |
<p>I have conducted a study where I employed a two-way repeated measures design to investigate whether subjects respond to a main treatment effect. What I'm mainly interested in is whether subjects subsequently compensate for the treatment effect by returning to a control level, or whether the initial differences persi... | g15621 | [
0.012594126164913177,
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-0.027257466688752174,
-0.033338822424411774,
0.007761447690427303,
-0.0017296663718298078,
0.05367448553442955,
-0.00796034000813961,
-0.019885247573256493,
0.012280485592782497,
-0.015931474044919014,
-0.0024603998754173517,
-0.034768443554639816... |
<p>I have modeled a distribution, $f$, over a r.v. $x \in \mathbb{R}^3$. At inference a set of measuring points, $X$, of the r.v. variables show up. I want to form a distribution over this sample set so that I can sample from it so that more probable points will show up more often. </p>
<p>My idea was to evaluate $f$... | g59842 | [
0.010161995887756348,
-0.02264546789228916,
-0.01805301010608673,
-0.008805213496088982,
-0.034754429012537,
-0.008920321241021156,
0.020902711898088455,
0.02349305897951126,
-0.048080213367938995,
-0.02524886652827263,
-0.004489216022193432,
-0.028277402743697166,
0.048325300216674805,
0.... |
<p>I am working with multiple binary vectors e.g., A,B,C,D,E,F,G,H. I want to find the classification between them. I have tried the following:</p>
<pre><code>log_data<-read.csv(choose.files(), as.is = T, header = T, blank.lines.skip = TRUE)
data<-log_data[2:ncol(log_data)]
data
TIME A B C D E F G
1 1 1 1 0... | g59843 | [
0.02743551880121231,
-0.05020793527364731,
-0.032594822347164154,
-0.058097440749406815,
0.011724147945642471,
-0.03330552577972412,
0.031296852976083755,
-0.024928385391831398,
-0.11535216122865677,
-0.0757543295621872,
0.004057581070810556,
0.011223351582884789,
0.03360063582658768,
-0.0... |
<p>I want to extract the weight and the bias for my dataset which has two columns and more than 3000 rows.
Also I want to draw a line by this equation:
y = w.x + b
where
w is the weight, x is the data point, and b is the bias.
Could anyone help me, please?
Regards,</p> | g59844 | [
0.031035101041197777,
0.0043112291023135185,
-0.016823474317789078,
-0.023729117587208748,
0.0013487434480339289,
-0.04043341055512428,
-0.008708108216524124,
0.03897552937269211,
-0.06746738404035568,
0.00041600572876632214,
-0.022353509441018105,
0.05424969270825386,
0.04916797950863838,
... |
<p>I apply Fisher's exact test on very very small sample size. Each location in the table would have about 1 or two samples. The fisher's method has no room to enumerate the the tables, and returns me a very bad result. So is there any other improved exact test for very tiny sample size data?</p> | g59845 | [
-0.0012915462721139193,
0.009940756484866142,
0.03722776100039482,
-0.04083830490708351,
-0.028740737587213516,
-0.04749457910656929,
-0.01304959412664175,
0.04281678795814514,
-0.057441599667072296,
0.008158492855727673,
0.0024809001479297876,
0.02842097170650959,
0.017039330676198006,
0.... |
<p>I am using MATLAB 2012a to run 3 tests. With my data, I obtain very small values, and for the Anderson–Darling (A–D) tests, the results are not even normalized.
Please verify my code. I am also using the A–D script which is found at <a href="http://www.mathworks.com/matlabcentral/fileexchange/14807-andartest" rel="n... | g15626 | [
0.07342862337827682,
-0.05802798271179199,
-0.011986477300524712,
-0.010610225610435009,
-0.002409984590485692,
0.03079616278409958,
0.01573105901479721,
-0.0071607427671551704,
0.0029363397043198347,
-0.053087055683135986,
-0.008758080191910267,
0.008243676275014877,
0.0494190938770771,
0... |
<p>I have some trouble with the last test I need to perform for my bachelor thesis. I have two variables and I need to test whether there is a significant difference. The first variable has all the returns of stocks on specific days. The second variable has these returns as well, however some days have been deleted. I ... | g59846 | [
0.030421627685427666,
-0.041289426386356354,
0.007579093798995018,
-0.03344111889600754,
0.0024300299119204283,
-0.033555444329977036,
0.02659745141863823,
0.008244073949754238,
-0.010364629328250885,
0.013466861099004745,
0.026681507006287575,
0.032054975628852844,
-0.006627919152379036,
... |
<p>For calculating Pearson Coefficient, i am using the below formula in MATLAB:</p>
<pre><code>C=cov(x,y);
p=C(2)/(std(x)*std(y));
</code></pre>
<p>But C(2) is zero in my case if </p>
<pre><code>x = [1 0 1 0 0 0];
y = [1 1 1 1 1 1];
</code></pre>
<p>Any idea where I am going wrong</p> | g15627 | [
0.02863560989499092,
-0.0367569662630558,
0.028672536835074425,
-0.036290787160396576,
0.06583402305841446,
-0.022017575800418854,
0.03262346610426903,
0.02061188966035843,
-0.07276667654514313,
0.009854665026068687,
-0.02825942263007164,
0.04415447264909744,
0.012254039756953716,
0.004105... |
<p>For two perfectly correlated Gaussian variables, the mutual information between them, and thus the KL divergence between the product of the marginal distributions and the joint distribution, is infinity. I have read that KL divergence is always finite if Q is continuous in respect to P, but I am having a hard time u... | g59847 | [
0.05437111854553223,
-0.013294791802763939,
-0.0026171694044023752,
-0.03640316054224968,
0.0101576903834939,
0.019996164366602898,
-0.06664223968982697,
0.05080639198422432,
-0.04441269859671593,
-0.033047258853912354,
-0.05019914358854294,
-0.06058294698596001,
0.004115627147257328,
-0.0... |
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