question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>If I observe the following:</p>
<p>$X \sim N(\mu_x,\sigma^2_x)$</p>
<p>$Y|X=x \sim N(x,\sigma^2_y)$</p>
<p>My objective is to calculate the marginal distribution of $Y$.</p>
<p>(Since the variance term does not address some form of correlation $\rho$, the dependence between both random variables clearly needs to... | g25876 | [
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<p>Is there a way to calculate an estimate of $\kappa$ from data for the von Mises distribution?</p>
<p>It seems very easy to do in R, <a href="http://rgm2.lab.nig.ac.jp/RGM2/func.php?rd_id=CircStats:A1inv" rel="nofollow">http://rgm2.lab.nig.ac.jp/RGM2/func.php?rd_id=CircStats:A1inv</a>, but python doesn't have an A1i... | g17983 | [
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<p>I'm interested in a changepoint detection problem of the following scenario:</p>
<p>Consider two Poisson processes for which we have the event times. I'm interested in detecting a change in the <em>relative</em> intensities of the processes, normalizing out fluctuations in the combined/joint intensity.</p>
<p>Fur... | g66724 | [
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<p>I've implemented baseline predictors model.
It trains on data: "<code>user_number item_number rating_ui</code>"
And then I need to predict raiting for "<code>user_number item_number</code>".
I use following formulas for biases:</p>
<pre><code>b_ui = average_rating + b_i + b_u;
b_i = (sum_(by all items)(rating_ui-a... | g775 | [
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<p>I'm looking at using a VARMA model to both determine the driver so value in some advertising campaigns and also to forecast future activity. I'm looking at the paper by <a href="http://www.sciencedirect.com/science/article/pii/S0148296397001859" rel="nofollow">Takada and Bass</a> as a reference point and I'm looking... | g66725 | [
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<p>After multiply imputing data, it is natural to estimate regression models on the data. When multiple predictors are available, sometimes stepwise regression is used for model building (forward inclusion or backward elimination of covariates). My question is how to use a similar procedure on multiply imputed data set... | g66726 | [
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<p>Survival data with censoring were generated by monte carlo method in R. Patients survival data was assumed to follow a weibull distribution. Parameters were extracted by fitting a parametric model to the simulated survival data with survreg. However, I got warning message: In survreg.fit(X, Y, weights, offset, init ... | g25880 | [
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<p>I have some time-series data that displays a count value for every day:</p>
<p><img src="http://i.stack.imgur.com/zXl9P.png" alt="enter image description here"></p>
<p>These count values begin at 1 or -1 and will continue to count up (or down) if conditions in the time series are met. If the conditions are not me... | g25881 | [
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<p>Suppose $y$ is a binary outcome variable and $x$ is a categorical predictor variable that takes three levels (1,2,3). In this case, you would create two dummy variables $x_2, x_3$. So $x_2=1$ if $x=2$ or $x_2=0$ if $x \neq 2$. Likewise $x_3=1$ if $x=3$ or $x_3=0$ if $x \neq 3$</p>
<p>A logistic regression model wou... | g66727 | [
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<p>I'm using R to do some time series estimation. I'm trying to rebuild the fitted values from an Arima model by hand to use in an Excel spreadsheet using the estimated coefficients and the input data. I can use the fitted command, but I'm trying to understand more how it works. Ex: </p>
<pre><code>library(MASS)
lib... | g25882 | [
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<p>I am currently working on a project the includes fitting. For the fitting I would like to try uniform random starting parameters. The possible fit parameters can lie in quite a large range, for example 10^-15 to 10^15 while others can lie in the range of -1 to 1. So quite diverse.</p>
<p>When I try to create random... | g66728 | [
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<p>I'm wondering what's the usual way for detecting "three-parts" association between variables. I'm not even sure about the name, so I apologize for any misunderstandings beforehand. Here is what I want. I suspect that buried behind some noise is a relation of this kind:</p>
<p>$$s=\begin{cases}
g(b) & \textrm{... | g25886 | [
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<p>We draw $n$ values, each equiprobably among $m$ distinct values. What are the odds $p(n,m,k)$ that at least one of the values is drawn at least $k$ times? e.g. for $n=3000$, $m=300$, $k=20$.</p>
<p>Note: I was passed a variant of this by a friend asking for "a statistical package usable for similar problems".</p>
... | g66729 | [
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<p>What fields of science (social or physical) use modelling for time-series analysis? In particular, time-series that cannot be replicated? Two examples that I can think of are climate modelling, and econometrics. Are there any others?</p>
<p>I am asking because I am doing research on model independence in climate sc... | g66730 | [
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<p>I have been wondering, why are LASSO and LARS model selection methods so popular even though they are basically just variations of step-wise forward selection (and thus suffer from path dependency)? </p>
<p>Similarly, why are General to Specific (GETS) methods for model selection mostly ignored, even though they do... | g25887 | [
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<p>I am looking at the relationship betwwen two interval level variables, being income and subjective well-being and I want to test the overall correlation as well as the correlation in three professional groups, namely doctors, high school teachers, and shop assistants.</p>
<p>If I use bivariate correlation, I will ... | g25893 | [
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<p>Suppose that we have $X_1,...,X_n$ ~ i.i.d $N(\mu,\sigma^2)$, where $\mu$ is unknown and $\sigma^2 = 1. $ Is the following estimator:</p>
<p>$\hat{\mu} = \frac{1}{n-1}\sum{x_i}$ consistent but not asymptotically efficient?</p>
<p>There are different definitions of what it means to be asymptotically efficient and h... | g19937 | [
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<p>I'm currently working on a project involving GLMs (and eventually GAMs) of some count data over time. Normally I'd do this in SAS, but I'm trying to move to R, and having...issues.</p>
<p>When I fit a GLM to count data using the following:</p>
<p><code>cdi_model <- glm(counts ~ exposure + covariate + month, dat... | g66731 | [
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<p>I am dealing with a data set containing roughly $n=4000$ <strong>binary</strong> observations $Y_1, \ldots, Y_n$ with $p=1000$ <strong>binary</strong> explanatory variables. I suspect that a lot of these explanatory variables are not relevant to the prediction of the observations. Moreover, it is clear that there ar... | g46287 | [
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<p>Hi Fellow Statisticians,</p>
<p>I have a source generating hashes (e.g. computing a string with a timestamp and other information and hashing with md5) and I want to project it into a fixed number of buckets (say 100).</p>
<p>sample hash:
0fb916f0b174c66fd35ef078d861a367</p>
<p>What I thought at first was to ... | g46288 | [
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<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/26060/derive-househould-weights-from-a-uniformly-distributed-person-sample">Derive househould weights from a uniformly distributed person sample</a> </p>
</blockquote>
<p><strong>EDIT</strong>: Essentially... | g49758 | [
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<p>I have a file containing questionnaire data (categorical data, 4 possible values). I have imported this to R to get the corresponding data frame. Now I've done some messy things with the table function to obtain a new data frame which contains instead of the whole data listing only the frequency counts in right orde... | g43254 | [
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<p>Here is a sequence of sample data where user is using some functionality:</p>
<ul>
<li>user_1 -> func_1</li>
<li>user_2 -> func_2</li>
<li>user_3 -> func_3</li>
<li>user_1 -> func_1</li>
<li>user_1 -> func_1</li>
<li>user_1 -> func_1</li>
</ul>
<p>Problem: How to calculate distribution of most popular functionalit... | g66732 | [
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<p>Let's say I have random variable $\mu \sim N(\mu ; 0, \xi^2)$. Is there anything useful known about the distribution of random variable $d = N(x ; \mu, \sigma^2)$, that is, the distribution of density at a fixed point $x$ given that the mean is a normally distributed random variable?</p> | g66733 | [
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<p>I have a four variable $(x_1, x_2, v_1, v_2)$ state space for a system of ODEs. I would like to build a random sample of the initial conditions for these ODEs --- in other words, I wish to build a sample of vectors $\{(x_1, x_2, v_1, v_2),... \}$ from some PDF. However, I require that these vectors satisfy a const... | g66734 | [
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<p>I want to use AIC to compare three candidate models (labeled by m), each having K_m parameters. However, I have M datasets over which I can make the comparison. My ultimate goal is to report the "relative goodness" of each of the three models for a single fit. How to I make use of the multiple datasets?</p>
<p>O... | g25900 | [
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<p>So I've been working on the same question in my homework for days. I've done it over and over and I know I'm doing something wrong. I can't get a straight answer from anybody about it. I just want to understand.</p>
<p>Right now, I'm pretty sure I've calculated my common standard deviation of the 5 varieties incorr... | g66735 | [
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<p><a href="http://stackoverflow.com/questions/7618052/whats-the-difference-between-a-uniformed-and-non-uniformed-histogram">This question</a> describes the basic difference between a uniform and a nonuniform histogram. And <a href="http://stats.stackexchange.com/questions/798/calculating-optimal-number-of-bins-in-a-hi... | g66736 | [
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<p>In my experiment I measure accuracy (0-1) in two groups, on two different types of stimuli. I use the generalized linear mixed model because I think this is the only model that can deal with binary DVs and with nested data (trials within the same participant).</p>
<p>SPSS syntax:</p>
<pre><code>GENLINMIXED
/DATA... | g46302 | [
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<p>I have some data resulting from a simulation that consists of several groups, each containing a single real datapoint and a variable number of matched controls. I take the rank of each real value within its distribution of controls, and normalize the ranks to between 0 and 1.</p>
<p>Now I would like to test whether... | g38050 | [
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-0.02357351966202259,
0.04001931846141815,
0.03826422989368439,
0.022600065916776657,
... |
<p>I'm analyzing the results of some simulation work using a Cox proportional hazard model, and I have what I perceive are a great many ties in the data, representing when a particular individual in the simulation was infected. For example, one of the (many) runs of this model:</p>
<pre><code>Time, Freq
1, 8
2, 9
3, 5... | g66737 | [
0.010804304853081703,
0.0009886894840747118,
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0.013238509185612202,
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0.043391767889261246,
-... |
<p><strong>Question</strong></p>
<p>Consider the following process:
$$2y_t-3y_{t-1}+y_{t-2}=\epsilon_t-\theta\epsilon_{t-1}$$
What is the model for the process $w_t=\Delta y_t = y_t-y_{t-1}$?</p>
<p><strong>Attempt</strong></p>
<p>I have solved the question in two ways, which seem to be giving conflicting answers.</... | g66738 | [
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0.07866901904344559,
0.019999979063868523,
0.05257010832428932,
0.0555439218878746,
0.0... |
<p>I have derived this likelihood function
\begin{equation}
\begin{split}
&-\frac{1}{N}\log L(\eta,\beta,\mathit{\Omega})\\
&=\frac{1}{2}\log (\sigma^2_{\varepsilon}+T\sigma^2_{c})+\frac{T-1}{2}\log\sigma^2_{\varepsilon}+\frac{1}{2}\frac{1}{\sigma^2_{\varepsilon}+T\sigma^2_{c}}\frac{T}{N}\sum_{i=1}^{N}\left(\ba... | g25906 | [
-0.03349251300096512,
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-0.03341761231422424,
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0.10891436785459518,
0.01787552423775196,
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0.040394894778728485,
-0.02634444646537304,
0.046895742416381836,
-0.006651516072452068,
0.0421... |
<p>I have multivariate time series data of the EURUSD financial vehicle. In this data each variable represents a different metric. There are ~200,000 rows and ~20 variables.
There are no NULL values for any variable at any row. All data is numerical.</p>
<p>Alongside this data, at each time point I have the univariate... | g66739 | [
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0.048840977251529694,
0.0019002691842615604,
0.057034607976675034,
-... |
<p>This is going to be a long question : </p>
<p>I have written a code in MATLAB for updating the weights of MLP with one hidden layer . Here is the code :</p>
<p>weights_1 : weight matrix for input to hidden layer
weights_2 : weight matrix for hidden to output layer </p>
<pre><code>function [ weights_1,weights_2 ] ... | g66740 | [
0.0001768184156389907,
0.026255639269948006,
0.0048104627057909966,
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0.05330941081047058,
0.0033006619196385145,
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-0.007651422172784805,
-0.03975836932659149,
0.0878095030784607,
0.03585756942629814,
0.02... |
<p>I am looking for a kernel as low pass filter that satisfy as:I must find a kernel that statisfies as follows:
<img src="http://i.stack.imgur.com/gVBYW.png" alt="enter image description here"> </p>
<p>In the my reference paper, the author suggest gaussian kernel that is
<img src="http://i.stack.imgur.com/uWltv.png" ... | g66741 | [
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-0.004328819923102856,
0.0013902956852689385,
0.014996449463069439,
0.027104364708065987,
... |
<p>I heard a story recently in which someone said if they wanted to kill somebody (and get away with it) they would do it with their car. They cited various statistics about the number of auto-related deaths (including car-on-pedestrians) coupled with additional stats about the number of drivers actually sentenced to ... | g25914 | [
0.029434502124786377,
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0.017545044422149658,
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0.06372609734535217,
-0.020... |
<p>I have been doing some reading about <a href="http://en.wikipedia.org/wiki/ANOVA_gauge_R%26R" rel="nofollow">gage R&R</a> and I have a simple application for it. I will be using ANOVA for performing my gage R&R. From my standpoint, most people seem to be using gage R&R to determine the relative contribut... | g25916 | [
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<p>The data I'm looking at is concerned with percentages of people who would recommend a hospital.</p>
<pre><code>E.g.
NOT PROBABLY DEFINITELY FREQ
hospital_1 10.0 80.0 10.0 100
hospital_2 20.0 50.0 30.0 200
</code></... | g25917 | [
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<p>Regression models (at least up to GLMs) do not traditionally require stationarity (although the requirement for the residuals is even stronger than stationarity).</p>
<p>ARMA-style time series models seem to always require stationarity. <strong>What other models always require stationarity?</strong></p>
<p>Vague ... | g720 | [
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0.0010005842195823789,
0.04717603698372841,
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0.025883719325065613,... |
<p>My Dissertation analysis method involves a Multivariate multiple moderated regression. Where I have 4 Dependent Variables (DVs) and 4 Independent Variables (IVs). My model 1 is testing main effects and model 2 is testing interaction effects. Here is what my code looked like:</p>
<pre><code>mod1<-lm(cbind(Perceiv... | g25918 | [
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... |
<p>I have been using the <a href="https://engineering.purdue.edu/~bouman/software/cluster/" rel="nofollow">GMM cluster package</a> by Bouman, for which I did not find any adaptation module online. Before I start off reading up on the GMM adaptation theory and implementing it, I did like to know if there are any other o... | g25920 | [
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0.0... |
<p>I just have 2 questions: </p>
<p>(1) If we can obtain samples from the posterior distribution, is there any need to try to compute posterior expectations and intervals analytically...? </p>
<p>(2) Also, I know that Monte Carlo methods will, in general, produce different results every time they are run, but how mig... | g66742 | [
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0... |
<p>I am reading the book Data Analysis: A Bayesian Tutorial. The book mentions it would be wrong to bootstrap a single data element and use the posterior pdf as the prior. I understand it would be wrong to do this but can you show me either mathematically or intuitively why this bootstrap idea is folly. </p> | g66743 | [
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0.001... |
<p>I am working on a homework problem for my probability class:</p>
<p>(Cramer Application) </p>
<p>A. Let $X_1, X_2, ... X_n$ be a sample from a distribution with pdf $f(x;p) = q^xp$. Determine the MLE of $p$</p>
<p>Solution: I was able to do this straight from the definition of of the distribution and the log-like... | g66744 | [
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0.050277646631002426,
... |
<p>When $Y = AX + \varepsilon$ (i.e., $Y$ comes from linear regression model),
$$\varepsilon \sim \mathcal{N}(0, \sigma^2 I) \hspace{1em} \Rightarrow
\hspace{1em} \hat{e} = (I - H) Y \sim \mathcal{N}(0, (I - H) \sigma^2_{})$$
and in that case residuals $\hat{e}_1, \ldots, \hat{e}_n$ are correlated and not independent. ... | g66745 | [
0.06313970685005188,
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0.028241368010640144,
0.04682657867670059,
0.00020605462486855686,
-0.0... |
<p>My study is about "Churn Risk Evaluation of College Students". I decided to use R software, already had a result for the survival probability of an old data (all the students already left or graduated), and also have identified the significant variable using Cox model analysis. </p>
<ol>
<li>I want to have an outpu... | g776 | [
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-0... |
<p>I did a bunch of searches on this but did not find anything conclusive. Does the generalized beta distribution of the second kind, also known as the generalized beta prime distribution, have a closed-form conjugate prior? If so, could someone tell me what it is, with a literature citation if you happen to have one h... | g42757 | [
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<p>I have heard this said by one of my professors, but he is not available for me to ask anymore.
But if this is the case then why are there others defined on the wikipedia page, and why do authors refer to higher order moments in papers??</p>
<p>Many thanks.</p> | g66746 | [
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... |
<p>Maximum entropy classifier is mostly used for Natural Language Processing, in which the datas are discrete. I learned the formalism from the paper <em>A maximum entropy approach to natural language processing</em> and understood most of it.</p>
<p>My question is,
how to apply the Maximum Entropy principle to do the... | g66747 | [
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<p>I have a binary logistic regression with 5 IVs and all of their 2-way interactions. I have reduced/removed multicollinearity between main variables and their interactions by centering the main variables. I have found one of the best models according to LRT. The model also accords reasonably with theory. Everything i... | g25925 | [
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<p>I have a set of binary vectors where each vector represents one day of occupancy in a house and consists of 48 elements (each element for 30 minutes of the day). Each element can be 1 meaning that house was occupied and 0 for non occupied house.</p>
<p>My task is to predict the next day based on the history of the ... | g66748 | [
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<p>Given a normal distribution of annual mean values (sunny days per year), I know the P50 and the annual uncertainty.</p>
<p>Is there any method to calculate the monthly uncertainty? Thank you very much.</p> | g25928 | [
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<p>Suppose one has a matrix of data $X$, which is $n$ observations by $p$ dimensions.</p>
<p>Let $P_\perp$ be a projection onto some $k<p$ dimensional subspace. Suppose one computes the principal direction of $P_\perp(X)$. Is there a principled way to reconstruct this principal direction in the full $p$-space?</p> | g25929 | [
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<p>Our client software randomly selects a server to connect to. There are four separate addresses the software randomly chooses from. Two addresses are "old" and two are "new". As many firms need to explicitly allow outbound access to IP addresses, there will be some firms (users of some firms) that cannot connect to t... | g25932 | [
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... |
<p>I have two data-sets for same samples. But they are produced using two different instruments. I want to choose one data-set for further analysis. How can I find/prove which data-set is better? <br/></p>
<p>To make it more simple - let's say we took photos of 50 males and 50 females using two different types of came... | g66749 | [
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<p>I have an interview with a top company for a data scientist position. I was made aware that they will be testing probability/statistical theory concepts. </p>
<p>So the question:</p>
<p>If you had 1 hour tops to do an all-inclusive interview about a range of topics, and wanted to test someone's knowledge of pro... | g49343 | [
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<p>I am somewhat familiar with various ways of testing mediation for factors in different types of regression analysis. (I'm using R and currently working with a multilevel binary logistic regression.) But now I have a situation in which I'd like to test whether one interaction between factors mediates another, and I... | g4765 | [
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<p>In an experiment with 5 technicians from different companies, we investigated effects of new equipments. The interested response variable is categorical. </p>
<p>One thing I am considering is that the technician effect is a random effect. But it's hard to include a random effect in the multinomial logistic model. I... | g66750 | [
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<p>I have data for several individuals that takes the following form over time. Many individuals are flat over the course of a year, meaning their measurements stay roughly the same. Others have a peak or two and are then flat. And others have many peaks. For each individual I must find an average (representative) valu... | g66751 | [
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0.... |
<p>My question is if data are in paired groups (before and after treatment), where the pre-treatment group is normally distributed and the post-treatment group is not normally distributed (i.e. it is skewed), then which test should be applied? Is the Wilcoxon sign rank test appropriate?</p> | g66752 | [
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0.02426145039498806,
0.0643981546163559,
0.00612611835822463,
-0.016019262373447418,
0.0016148725990206003,
0.06253327429294586,
-0.026119155809283257,
-0.00... |
<p>How is a random forest model affected if some of the variables are not independent? </p> | g66753 | [
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0.05265... |
<p>My question is very closely related to a previous post
<a href="http://stats.stackexchange.com/questions/51520/error-term-in-repeated-measures-anova-in-r">Error term in repeated measures ANOVA in R</a>
However, I would like to get more insight into how to define the error term.</p>
<p>Suppose I have a two-way repe... | g66754 | [
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0.02150464989244938,
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... |
<p>I would like to understand what the following code is doing. The person who wrote the code no longer works here and it is almost completely undocumented. I was asked to investigate it by someone who thinks "<em>it's a bayesian logistic regression model</em>"</p>
<pre><code>bglm <- function(Y,X) {
# Y is a ve... | g66755 | [
-0.020768335089087486,
-0.004193217493593693,
-0.013903122395277023,
-0.015208834782242775,
0.04093160107731819,
-0.02184983156621456,
0.029590552672743797,
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-0.05029314383864403,
-0.07407073676586151,
0.00913106556981802,
0.0805281549692154,
-0... |
<p>I have 82 respondents in 2 groups (43 in Group A and 39 in Group B) that completed a survey of 65 Likert questions each ranging from 1 – 5 (strongly agree - strongly disagree). I therefore have a dataframe with 66 columns (1 for each question + 1 indicating group allocation) and 82 rows (1 for each respondent). </p>... | g66756 | [
0.04212353751063347,
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0.026927299797534943,
0.0324053093791008,
-0.008321795612573624,
0.06910523027181625,
0.0055353399366140366,
0.05705813691020012,
-0.012... |
<p>I am currently building a statistical model. According to data, the variance is non-constant, and it is likely based on a factor. Is there any statistical model with variance as a function of other parameters? What is its name, and can that model be fitted in R?</p> | g777 | [
0.04024198278784752,
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0.00518611678853631,
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0.007443986367434263,
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... |
<p>I'm brand new to statistics and am studying the math behind split testing (A/B and multivariate). I've learned how to calculate $\chi^2$ with given test data, and I understand how to translate this into a probability via a table, but I'd like to be able to calculate the probability myself. I've read through a couple... | g4786 | [
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0.02799624390900135,
-0.0... |
<p>The residuals have an AR(2) structure. Is it appropriate to add AR terms to a fixed-effects panel model?</p> | g66757 | [
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<p>Penalized models can be used to estimate models where the number of parameters is equal to or even greater than the sample size. This situation can arise in log-linear models of large sparse tables of categorical or count data. In these settings, it is often also desirable or helpful to collapse tables by combining ... | g25937 | [
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<p>I am running a GLM, using the function glm.nb (pscl package) trying to figure how what could influence a particular trait in several locations and years. The output as follow (with slight modification and removing the things beyond this question)</p>
<pre><code> Estimate Std. Error z value Pr(>|z|)
... | g66758 | [
0.03260370343923569,
-0.06002594530582428,
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-0.043795693665742874,
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0.08845222741365433,
0.02194913849234581,
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-0.020800059661269188,
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0.05258769541978836,
0.012389466166496277,
-0.0... |
<p>I have the cardinalities of sets $N_i, \forall i \in 1,2..n$, and the cardinalities $|N_i \cap T|, |N_i|, |T|, |N_i \cup T|, \forall i$, are known. </p>
<p>Here, the set $T$ and sets $N_i$'s are all subsets of a mother :) set M and $|M|$ is also known.</p>
<p>Using these quantities, I would like to compute the no... | g66759 | [
0.01858593337237835,
0.0343758687376976,
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0.019591310992836952,
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-0.012430674396455288,
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0.04789568856358528,
0.... |
<p>Imagine, that we measured two values and we know, that in reality one measurement directly corresponds to the latent variable "s1", and the other measurement is in fact sum of two values: "s1" and unknown "s2". Given the measurements input<a href="http://doing-bayesian-data-analysis.12272.x6.nabble.com/How-to-model-... | g66760 | [
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0.054993413388729095,
0.03883232921361923,
... |
<p>I stumbled upon this term in <em>McFadden - Analysis of qualitative choice behavior</em> (page 111).</p>
<p>It is said that </p>
<blockquote>
<p>"A random Variable $X$ is <em>translation complete</em> if for a function <em>h</em>
of bounded absolute variation with $h(\pm\infty)=0$, the condition
$E(h(X+a))=0... | g66761 | [
0.030929580330848694,
0.026827780529856682,
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0.02921820431947708,
0.008073175325989723,
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0.014822292141616344,
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0.06031502038240433,
-0... |
<p>I have my set of documents and have extracted the unique words from them, including a count of the number of times each word appears in the document. But it would seem from the documentation on the <a href="http://radimrehurek.com/gensim/tut2.html" rel="nofollow">Python library I'm using</a>, that word count within... | g46345 | [
0.0023431500885635614,
0.028712838888168335,
0.007159541826695204,
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0.014734853059053421,
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0.011916665360331535,
0.07592681050300598,
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0.03787713125348091,
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0... |
<p>I have some data where I've measured the response times of the same participants in two sessions and within 36 conditions (each participant took part in all 36 conditions). So the data are repeated measures across both IVs, however I've been informed that I can run it as though it was an independent-measures ANOVA b... | g66762 | [
-0.004058717284351587,
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0.015907615423202515,
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... |
<p>My lab has data from an experiment with a treatment and a control, and pre and post tests. The data will be analyzed by standard 2X2 repeated measures ANOVA.</p>
<p>However, the response variable is of cell counts in tissue expressed as a percentage of total cells. There are many subjects with 0%'s and the rest som... | g25942 | [
0.0228478591889143,
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-0.030429262667894363,
0.013190885074436665,
0.01941353641450405,
0.024504657834768295,
... |
<p>I have multiple time series where at any point in the time series, an event can occur that I believe has an effect on the time series. This event can happen at different times for each of the different time series. How would I go about estimating the effect of this event on a time series where the event has not yet ... | g4830 | [
0.0028698064852505922,
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0.030230166390538216,
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0.016742199659347534,
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-0.06772027909755707,
-0.00009098395821638405,
-0.056326162070035934,
0.006786791142076254,
-0.004175125621259212... |
<p>Could I please check if there are any theoretical or practical pitfalls if one uses implementations of the $k$-sample Anderson-Darling test [3] to perform the two sample Anderson-Darling test [1,2]? For example, there is the R package adk, which is an implementation of the $k$-sample Anderson-Darling test.</p>
<hr>... | g66763 | [
0.046367865055799484,
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0.04635421559214592,
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0.0051660193130373955,
0.05559288710355759,
0.022... |
<p>I'm testing the sensitivity of different factors on the benefits of precision irrigation. The change in the inputs is changing the output but not significantly.
How is it possible to do a regression for these factors?</p> | g25249 | [
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0.056659795343875885,
0.05678471922874451,
0.... |
<p>Random Forests work by creating an ensemble of decision trees where each tree is created using a bootstrap sample of the original training data (sample of both input variables and observations).</p>
<p>Can a similar process be applied for linear regression?
Create k linear regression models using a random bootstrap... | g25946 | [
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0.02774111181497574,
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0.0327112153172493,
0.0... |
<p>For clustered data, how would you interpret the coefficients? Would you just exponentiate the coefficient to get an odds ratio? </p> | g66764 | [
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0.02348354086279869,
0.039975009858608246,... |
<p>I have some data (a set of numbers) and I want to compare them with the normal distribution using QQ-plot. The only statistical tool that I am aware of is Octave but Octave doesn't draw the reference line.</p>
<p><img src="http://i.stack.imgur.com/RMTrF.png" alt="enter image description here"></p>
<p>As can be see... | g25949 | [
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0.001323107397183776,
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0.03204967454075813,
-0.01558... |
<p>In May 2010 Wikipedia user Mcorazao added a sentence to the <a href="http://en.wikipedia.org/wiki/Skewness">skewness article</a> that "A zero value indicates that the values are relatively evenly distributed on both sides of the mean, typically but not necessarily implying a symmetric distribution." However, the wik... | g66765 | [
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0.004527417477220297,
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<p>Much like with regression, handling binary dependent variables in SEM requires special considerations. In particular, some of these are noted on Dave Garson's <a href="http://faculty.chass.ncsu.edu/garson/PA765/structur.htm" rel="nofollow">Structural Equation Modeling</a> and include:</p>
<blockquote>
<ol>
<li>... | g37466 | [
0.028014790266752243,
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0.006543305702507496,
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0.02471645548939705,
0.03879198431968689,
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0.028636112809181213,
-0.021219588816165924,
0.042548615485429764,
... |
<p>To cluster (text) documents you need a way of measuring similarity between pairs of documents.</p>
<p>Two alternatives are:</p>
<ol>
<li><p>Compare documents as term vectors using <strong><a href="http://nlp.stanford.edu/IR-book/html/htmledition/dot-products-1.html#8077">Cosine Similarity</a></strong> - and TF/IDF... | g25951 | [
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0.016962992027401924,
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-0.009273811243474483,
0.024379907175898552,
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0.09123601019382477,
... |
<p>(Background info <a href="http://mathiology.blogspot.nl/2014/04/logistic-regression-with-gradient_7.html" rel="nofollow">taken from my blog</a>)
In logistic regression, the hypothesis function, which models the relationshiop
between the dependent variable $P(y = 1)$ and the independent variable $X$, is
:
\begin{... | g66766 | [
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-0.017985988408327103,
-0.033265113830566406,
0.04784457013010979,
0.019371094182133675,
... |
<p>I'm trying to fit a discrete-time model in R, but I'm not sure how to do it.</p>
<p>I've read that you can organize the dependent variable in different rows, one for each time-observation, and the use the <code>glm</code> function with a logit or cloglog link. In this sense, I have three columns: <code>ID</code>, <... | g25954 | [
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0.04310004040598869,
... |
<p>I'm new to SAS coding from SPSS point and click. I don't currently have SPSS, so SAS is my only option.</p>
<p>My question is: how do I get the percent variance explained and cumulative variance explained following varimax rotation?? I get the total that I would get under
'Rotation Sums of Square Loadings' but not... | g42973 | [
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... |
<p>I need to manually calculate multi-step prediction intervals for time series data. I know packages like 'forecast' in R provide these, but I cannot use these packages as the production infrastructure does not support R. </p>
<p>Could someone point me to an article that explains how to generate multi-step prediction... | g66767 | [
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0.024011928588151932,
-... |
<p>I have a study where they randomized patients into 2 groups (A and B). The primary aim is to compare group A against a fixed/ true value of 0.75. The binomial test is not stratified and cochran mantel haenszel needs 2 groups. How can I perform a stratified test for risk differences against a true value? </p> | g189 | [
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<p>To calculate the PDF function using Shannon entropy I have scaled my original sample by simply doing $x'=(x-a)/(b-a)$; where $b=\text{max}(x)$, and $a=\text{min}(x)$ and then I found the $\text{PDF}(x')= exp(-\lambda_0-\lambda_1x'-\lambda_2x'^2)$ using optimization with subjection to moments constraints. However it'... | g66768 | [
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-0.0230... |
<p>I need to calculate the positive predictive value for a validation set for a rare event. The problem is that the validation set was oversampled for the rare event. The event occurs in 5 percent of the population, however the oversampling has adjusted it to be in 50 percent of the sample. </p>
<p>How does the oversa... | g25958 | [
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0.... |
<p>Survival times are often right censored and left truncated. From my experience, it does not seem like OpenBUGS allows for both. Truncation is denoted as T( , ) and censoring as C( ,).
For instance, a censored observation known to lie above 10 days, but cannot have been observed below 2 days (left truncation) seem li... | g66769 | [
-0.0069034588523209095,
-0.03514699637889862,
-0.006804889068007469,
-0.045315150171518326,
0.02785502001643181,
0.011944865807890892,
0.004789937753230333,
0.02462850697338581,
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-0.006821304094046354,
-0.019869090989232063,
-0.03647489845752716,
0.009001231752336025,
... |
<p>I have read about eigen faces and eigen voices etc in signal processing which involves PCA. They used to refer to the principal components selected to process for image recognition etc. But now I heard from somewhere about eigen gene in genetics and computational biology. OK if they are the principal components, how... | g66770 | [
0.029447082430124283,
-0.05581490695476532,
0.01788075640797615,
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0.027257246896624565,
-0.015500234439969063,
0.07211826741695404,
0.04629489779472351,
-0.029483109712600708,
-0.046447597444057465,
0.005426593590527773,
0.02429180033504963,
0.08769334852695465,
0.008498... |
<p>I want to create two random variables $X \sim N(0,1)$ and $Y \sim N(0,1)$ that satisfy $E(X,Y)=0.5 $</p>
<p>That is I want to create $Z=(X,Y)^\top $ with a joint bivariate normal distribution</p>
<p>$ Z \sim N\left( \left(\begin{array}{c} 0\\ 0 \end{array}\right) , \left(\begin{array}{cc} 1 & 0.5\\ 0.5 & 1... | g49376 | [
0.01014414057135582,
-0.061487819999456406,
-0.01679227314889431,
-0.03101939521729946,
0.012846369296312332,
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0.007270453963428736,
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0.031512148678302765,
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0... |
<p>I want to compare 6 designs of spoons (D1,D2,D3,D4,D5,D6) in 20 children (blocks).I also want to see whether holding the spoon in right or left hand affects food-pinching response(number of M&M's picked and placed in cup).
I have dataset with response % noted for each design type on all of the 20 children, and ... | g66771 | [
-0.021092090755701065,
-0.010375351645052433,
-0.0035511988680809736,
-0.03056165762245655,
-0.023973045870661736,
0.009934513829648495,
0.0523260198533535,
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-0.0014001448871567845,
-0.0198807530105114,
0.031377341598272324,
0.02837962843477726,
... |
<p>It is a homework question from coursera course Core Concepts in Data Analysis.</p>
<p>I think we need to know at least variance of $X$ to calculate the value. </p>
<p>The staff gives a hint we can calculate it with the coefficient of determination. But I have no idea what the coefficient is. </p> | g66772 | [
0.021902654320001602,
0.028220366686582565,
-0.02298637479543686,
-0.013318367302417755,
0.04219464212656021,
-0.03729776665568352,
0.04149023815989494,
0.017943499609827995,
-0.016594700515270233,
-0.0605609193444252,
-0.06343997269868851,
0.10081861913204193,
0.010569979436695576,
0.0077... |
<p>I'm analyzing two financial time series with Johansen method. A high Correlation coefficient using the Pearson method will help me to detect spurious cointegration models to avoid? </p>
<p>If this is not the case, which is the best method would provide clue about it? </p>
<p>Thank you</p> | g66773 | [
0.09187409281730652,
0.016903914511203766,
0.027110831812024117,
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0.03538815677165985,
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0.03838197514414787,
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0.013755656778812408,
-0.023798462003469467,
-0.003212554147467017,
0.03767847269773483,
0.00... |
<p>In <a href="http://stats.stackexchange.com/questions/41394/list-of-situations-where-a-bayesian-approach-is-simpler-more-practical-or-more">this</a> community wiki page a twice-upvoted comment asserted by @probabilityislogic asserted that "Multi-level modelling is definitely easier for bayesian, especially conceptual... | g66774 | [
0.004832219332456589,
0.04535845294594765,
0.008137723430991173,
0.016798097640275955,
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0.007962498813867569,
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0.0697190910577774,
0.... |
<p>I have a time series which I can preprocess by using centering and scaling. </p>
<p>In this respect I have the following questions</p>
<ol>
<li><p>Should I preprocess the response as well as the variables or only the predictive variables? </p></li>
<li><p>If I preprocess the dependant variable as well as the indep... | g66775 | [
0.04889655113220215,
-0.0013192410115152597,
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0.010418393649160862,
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0.007065772544592619,
0.02316884696483612,
0.002144238445907831,
-0.012576621025800705,
0.007513177115470171,
0.04046521708369255,
0.0008921998669393361,
0... |
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