question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I am using a binomial GLMM to assess differential habitat selection between two species with model selection using AIC. </p>
<p>When I use many variables (8), the models converge but are not significant. However, when I reduce the number of variables the models either do not converge or have an AIC of 'Inf'. </p>... | g39132 | [
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<p>In general, I'm wondering if there it is ever better not to use orthogonal polynomials when fitting a regression with higher order variables. In particular, I'm wondering with the use of R:</p>
<p>If <code>poly()</code> with <code>raw = FALSE</code> produces the same fitted values as <code>poly()</code> with <code>... | g62774 | [
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<p>When deconstructing my mixed effects model, I found a three-way significant interaction. I calculated my p-value by using maximum likelihood ratio tests allowing for a comparison of the fit of the two models (the model with all predictors minus the model with all predictors but the predictor of interest - in this ca... | g584 | [
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<p>I'm doing principal component analysis (PCA) on my nutrition data. Basically, I want to condense 43 food groups into fewer groups (aka, I want to define 2-3 patterns based on the 43 food groups). The problem is, my Kaiser-Meyer-Olkin (KMO) measure is very low (~0.35) but my Barlett's test for sphericity remains sign... | g38075 | [
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<p>I have a panel dataset on seaborne shipment prices for a sample of trading routes. The data is a fixed annual price, based on a) port costs and b) fuel (a function of distance and fuel price). The major unobserved variable is port cost, which differs by port, though may be similar by area. Each observation is a port... | g62775 | [
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<p>This may be both a stats and economics question.</p>
<p>Let's say that I am bidding in an auction for emails. There are 10,000 + plus emails and there are five bidders and each of us bids on a SINGLE email throughout the day as they become open to bids. The highest bidder wins the auction. Our revenue comes from us... | g7083 | [
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<p>Is there any R package that can produce cube plots for <strong>2</strong> factors (in fact it is a <strong>square</strong> plot)? I want something similar to the first plot at the end of <a href="http://www.processma.com/resource/factorial_plots.htm" rel="nofollow">this page</a> on factorial plots. </p>
<p>In the ... | g62776 | [
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<p>In explaining simple linear regression, isn't it a bit misleading for many examples to illustrate a straight line going through some scatterplot? This seems to suggest that linear regression only works if your independent and dependent variables have some sort of straight-line relationship, whereas the "linear" in l... | g20007 | [
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<p>I have a dataset which is statistics from a web discussion forum. I'm looking at the distribution of the number of replies a topic is expected to have. In particular, I've created a dataset which has a list of topic reply counts, and then the count of topics which have that number of replies.</p>
<pre><code>"num_re... | g62777 | [
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<p>Would appreciate any references to specific places where these terms are clearly defined. Thanks!</p> | g5477 | [
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<p>I was reading the multiple regression chapter of <a href="http://rads.stackoverflow.com/amzn/click/0521762936" rel="nofollow">Data Analysis and Graphics Using R: An Example-Based Approach</a> and was a bit confused to find out that it recommends checking for linear relationships between explanatory variables (using ... | g20011 | [
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<p>I'm debating taking some classes on statistics.com and was curious if anyone has taken classes there or knows any one who has or has any suggestions for good ways to learn stats/machine learning on the cheap-ish and on-line. </p>
<p>NOTE: I'm already signed up for Andrew Ng's ML class for spring '12. </p>
<p>Than... | g62778 | [
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<p>I am working on a problem to predict a value between 0 and 1. The data is skewed, so that only 18% of the values are greater than 0.</p>
<p>I implemented a machine learning system, and what is happening is that the lowest error rate on the validation set (18%) is found when all predictions are 0.</p>
<p>So, I want... | g39141 | [
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<p>The holiday season has given me the opportunity to curl up next to the fire with <em>The Elements of Statistical Learning</em>. Coming from a (frequentist) econometrics perspective, I'm having trouble grasping the uses of shrinkage methods like ridge regression, lasso, and least angle regression (LAR). Typically, I'... | g39142 | [
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<p>Julian Faraway, in his book on linear model with R, used half normal plot to find hat(a value in hat matrix) with too large value.</p>
<p>That's the only example where I saw half normal distribution is used. But other than that, I can't come up with real application of it though I guess it might be useful for appro... | g20012 | [
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<p>I have a large $(10000 \times 5001)$ table representing $10000$ samples and $5001$ different features of these samples. One of these features represents an output variable of each sample. In other words, I have $5000$ input variables and one output variable for each sample.</p>
<p>I know that most of these inputs a... | g49653 | [
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<p>I have 4 models in the hierarchical regression output. The models are as follows:
Model 1: Control variable
Model 2: Control variable and 11 independent variables.
Model 3: Control variable, 11 independent variables and moderator.
Model 4: Control variable, 11 independent variables, moderator and interaction terms.<... | g20017 | [
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<p>I have a 2D square, and I have a set of points inside it, say, 1000 points. I need a way to see if the distribution of points inside the square are spread out (or more or less uniformly distributed) or are they tending to gather together in some spot inside the square.</p>
<p>I need a mathematical/statistical (not ... | g62779 | [
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<p>I am attempting to use a Naive Bayes classifier to classify text. To accomplish this I have created an Excel sheet with a binary distribution for three variables. The workbook can be found <a href="https://dl.dropbox.com/u/9568360/Naive%20Bayes%20Classification.xlsx" rel="nofollow">here</a>. Assuming that my math is... | g62780 | [
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<p>I have a design where a number of object pairs were rated for association strength. These pairwise association ratings along 5 criteria of interest are expected to be used as IVs in a regression. </p>
<p>These pairs include a target object being paired with one of 4 accompanying objects to create the different type... | g20021 | [
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<p>I have this data </p>
<pre><code>data <- as.data.frame(cbind(y,x1,x2,pre))
data$x1 <- as.factor(data$x1)
data$x2 <- as.factor(data$x2)
data$x1 <- C(data$x1, contr.treatment, base=3)
data$x2 <- C(data$x2, contr.treatment, base=2)
y x1 x2 pre
1 16 1 1 14
2 15 1 1 13
3 14 1 2 14
4 13 1 ... | g62781 | [
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<p>This is for modeling revenue by looking at historical data. </p>
<p>I am trying to estimate a curve where $x$ = Fiscal Year Quarter and $Y$ = % of Revenue for lifetime of a bid(sale/opportunity/whatever term makes the most sense to you...)</p>
<p>The goal of this is so when a sales person puts in a bid that says "... | g62782 | [
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<p>I have cross classified data in a 2 x 2 x 6 table. Let's call the dimensions <code>response</code>, <code>A</code> and <code>B</code>. I fit a logistic regression to the data with the model <code>response ~ A * B</code>. An analysis of deviance of that model says that both terms and their interaction are significant... | g62783 | [
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<p>I have data for about 1 year, 100 observations, multiple observations per subject, transactions occur on weekly basis but have 6-12 subjects per week, there is no order to this. There is a policy change in latter half of year, I want to model change in dependent variable due to policy change as a dummy variable: tim... | g62784 | [
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<p>Why is the average of the highest value from 100 draws from a normal distribution different from the 98% percentile of the normal distribution? It seems that by definition that they should be the same. But...</p>
<p>Code in R:</p>
<pre><code>NSIM <- 10000
x <- rep(NA,NSIM)
for (i in 1:NSIM)
{
x[i] <... | g62785 | [
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<p>I have bought a book on factor analysis (on PCA more precisely) because it seems to be the algorithm that fits the most to mine my data.</p>
<p>Here is the context: I have a table of "subject x variables", each line is a subject (there are numerous subjects) and each column is a variable (here it is network variabl... | g34547 | [
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<p>According to Davison and Hinkley's book "Bootstrap Methods and their Application", page 154, based on an <code>RxN</code> array where <code>R=999</code> is the number of simulations and <code>N</code> is the number of ordered samples (smallest to largest) in each row, we could construct:</p>
<ol>
<li><strong>pointw... | g62786 | [
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<p>I'm using the following function to calculate Edwards R^2 (formula 19 in Edwards et al. 2008) of a mixed effects model (I hope the implementation is correct):</p>
<pre><code>r2lmer <- function(model) {
require(aod) # need the aod package for wald.test function
if (class(model) != "mer") stop("mer object ex... | g62787 | [
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<p>Consider the following model</p>
<p>$$
X \sim |\mathcal{N}(X;0,1)|
$$
$$
Y|X \sim Q(Y;X)
$$
where I define $Q(Y=-x|X=x)$ with probability mass $\int_{-\infty}^{-x}\mathcal{N}(x;0,1)dx$, $Q(Y=+x|X=x)$ with probability mass $1-\int_{x}^{\infty}\mathcal{N}(x;0,1)dx$, and the density of $Q(Y|X=x)$ equivalent to a t... | g20030 | [
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... |
<p>I have two sets of coefficients from similar data taken at different times. What I want to do is combine the two sets of coefficients giving greater weight to the more most recent set.</p>
<p>The goal is building a predictive model. So say I have dataset A from 2009, and dataset B from 2010.</p>
<p>My coefficien... | g5663 | [
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... |
<p>A Poisson regression is a <a href="http://en.wikipedia.org/wiki/Generalized_linear_model">GLM</a> with a log-link function.</p>
<p>An alternative way to model non-normally distributed count data is to preprocess by taking the log (or rather, log(1+count) to handle 0's). If you do a least-squares regression on log-... | g49577 | [
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-0.037596799433231354,
0.02934427559375763,
0.011076366528868675,
-0.0032276923302561045,
-0.07305518537759781,
-0.03436785563826561,
-0.01751355454325676,
-0.004816764499992132,
... |
<p>car packages's <a href="http://finzi.psych.upenn.edu/R/library/car/html/Ellipses.html" rel="nofollow">ellipse function</a> asks for a <code>radius</code> parameter. In help says that is the "radius of circle generating the ellipse". Could you please tell me which circle is this?</p>
<p>Thank you very much</p> | g62788 | [
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<p>I would like to generate datasets which has 3 treatment groups: A, B, and C based on 3 covariates: $x_{1}$, $x_{2}$ and $x_{3}$. The $x_{1}$ and $x_{2}$ are standard normally distributed and $x_{3}$ is Bernoulli (0.5) distributed. Besides these, assume risk difference between A & B = -0.36, A & C = -0.26 and... | g20033 | [
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... |
<p>I am designing a study for my project.
I wanted to test if music affects reading comprehension. This study will be a between group design. The independent variable is type of music and the dependent variable is the score on a reading comprehension task. </p>
<p>Half of participants will be randomly assigned to a r... | g49914 | [
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0.037... |
<p>I heard from an university course that a normal method for turning categoric variables into binary variables was to simply create a binary variable for each category (one-out-of-K coding). However, these variables should be standardized so the weight of the original variable remains unchanged.</p>
<p>How should the... | g62789 | [
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... |
<p>How can I show that, $U$ and $V$, two independent uniform $(-1,1)$ random variables have a conditional distribution, given that $U^2 + V^2 <1$, that takes the form:</p>
<p>$$f_{U,V|U^2+V^2<1} (u,v|w<1) =1/{\pi}, \quad u^2+v^2<1$$</p>
<p>I tried using the CDF technique for $W=U^2+V^2$</p>
<p>$$ \frac{P... | g62790 | [
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<p>I will soon have the results of a questionnaire that I have carried out, and I have made a plan on how I will analyse the data. I was hoping that someone could comment on my plan to advise me.</p>
<p>About the questionnaire: there are 3 groups of people (let's call them <code>A</code>, <code>B</code>, and <code>C</... | g20039 | [
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... |
<p>Im trying to measure the absolute change between two means of systolic bloodpressure, and used a simple method for calculating the confidence interval between to means. </p>
<p>My goal is to estimate the absolute change for the TREND between 1980-2000. So to accomplish this im comparing the first and last year (i.e... | g62791 | [
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<p>Would someone please tell me what an F test is and what is shows? Also what is an alpha? And how do I evaluate the p values? I posted two questions earlier and one was 'put on hold' because it was not in the right place, and the second one was marked as a duplicate because of the one put on hold. Neither of which an... | g34551 | [
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<p>i have a list of text files and i know that these texts belong to a group, by using this group of text files (i.e this is my sample set) i'd like to calculate <a href="http://en.wikipedia.org/wiki/Jaccard_index" rel="nofollow">Jaccard index</a> and <a href="http://en.wikipedia.org/wiki/Edit_distance" rel="nofollow">... | g6055 | [
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<p>I've been learning (lurking) from this site for a while and I finally have a question I haven't seen answered yet.</p>
<p>I'm doing a flight test and trying to fit the resulting data to linear line. From a combination of ~14 different sensors, I can calculate the 2 values of interest. From uncertainty propagation, ... | g62792 | [
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-... |
<p>From what I understood, these models differ from CARTs for regression, mostly because they fit a linear model at the leaves of the tree instead of simply taking an average. They also "smooth" the tree by generating linear models in the intermediate steps of the tree growth process.</p>
<p>I have been using the R im... | g44013 | [
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<p>I am building a binary logistic regression model. I am not sure if using the variables as interactions is a better choice than building separate models for level of a categorical variable. Is there a way to determine this? For ex, there are 2 categorical variable with 2 levels each -
1.Regions - East and West
2.AG... | g62793 | [
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<p>I was reading this <a href="http://www.nada.kth.se/kurser/kth/2d5342/kurspaket/aykroyd96bayesian.pdf" rel="nofollow">paper</a> related to Gaussian Markov Random field. I didn't get how they derived this equation from the standard multivariate gaussian distribution equation</p>
<p><img src="http://i.stack.imgur.com/... | g62794 | [
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<p>I used mvpart to produce a classification tree (response variables concerning travel behaviour, explain variables are socio-demographic). In the output I can see the averages of the travel behaviour variables for the different segments formed by the tree. Is there a way to test if these differences are statistical s... | g20043 | [
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<p>For a university course, a friend of mine had to test whether there is a relation between two ordinal variables. These variables were opinion about the European Union (positive, neutral, negative) and whether people felt being (a) citizen of their country, (b) primarily citizen of their country, but also European, (... | g614 | [
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<p>I'm trying to specify a model in JAGS/rjags with one between subjects factor (<strong>a</strong>, with two levels - <em>Y</em>, <em>N</em>) interacting with one repeated measures continuous variable <strong>x</strong> plus subject varying slopes and intercepts that correlate. I can specify this model simply enough w... | g20046 | [
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<p>I'm experimenting with random forests with scikit-learn and I'm getting great results of my training set, but relatively poor results on my test set...</p>
<p>Here is the problem (inspired from poker) which I'm trying to solve:
Given player A's hole cards, player B's hole cards and a flop (3 cards), which player ha... | g62795 | [
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<p><strong>Is it possible to generate means and standard deviation for two groups from a Cohen's d effect size?</strong></p>
<p>Even if the means and standard deviations are trivial/meaningless values, I would like to keep the same effect size.</p>
<p>The formula for Cohen's d is as follows:</p>
<pre><code>d = (mean... | g62796 | [
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<p>I am looking at following books:</p>
<ul>
<li>Statistical Models (Cambridge Series in Statistical and Probabilistic
Mathematics) - A. C. Davison</li>
<li>Essentials of Statistical Inference (Cambridge Series in Statistical
and Probabilistic Mathematics) - G. A. Young</li>
<li>Asymptotic Statistics (Cambridge Series... | g62797 | [
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0.02497291751205921,
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<p>I'm going to teach classes on Physics Laboratory on First year of Bachelor studies. In most of the excercises during data analysis students will have to fit a line to measurements they have taken. </p>
<p>I need formulas that fit data to the model:</p>
<p>$$
y_i = Ax_i + B + \epsilon_i
$$</p>
<p>Where $\ep... | g62798 | [
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<p>Consider the following question.</p>
<blockquote>
<p>Consider the generation of random numbers following an exponential distribution with some known mean. Give three reasons why the rejection-acceptance method would not be the preferred approach for generating random numbers for this distribution. What is the pre... | g62799 | [
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<p>I know what the term "posterior distribution" means (namely the conditional probability distribution of some parameter with respect to some observed data), but I'm reading an author that uses the qualifier "posterior" <em>all over the place</em>, mostly in contexts that I can't make any sense of.</p>
<p>For example... | g20056 | [
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0.030201120302081108,
0.011576781049370766,
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-0... |
<p>I have a set of laws/policies that overlap with each other through time (for example one started in 1990 and finished in 2001, and the other started in 1995 and finished in 1999). I want to examine how the interaction of those two influence my dependent variable. I am using spss, and I was thinking to set the indepe... | g20054 | [
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0.029001016169786453,
0.011631172150373459,
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0.... |
<p>I need help in calculating the goodness of fit for a Poisson model. The online literature on it is quite scarce, so if you have any useful articles and links I would appreciate it very much.</p>
<p>Here is how the table looks like from SPSS. The outcome variable is a count of patents a company has.</p>
<p><img src... | g62800 | [
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-0.... |
<p>I am looking for help in the following situation: </p>
<p>I have a set of numbers $A=\{1, 2, \dots, 100\}$, and I am drawing subsets of 10 of these numbers $\{a_1, a_2, \dots, a_{10}\}$ according to an underlying distribution that I do not know. After doing this procedure $N$ times (which can be very large), I woul... | g62801 | [
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... |
<p>I am trying to do a priori sample size calculation based on published results. However, I am unable to obtain a reasonable estimate of the published effect size (which is not reported) as I am unable to obtain an estimate of the pooled standard deviation or the standard deviation of the difference.</p>
<p>The probl... | g20059 | [
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... |
<p>I've been involved in a machine learning project recently and am now in the process of writing the project up for a paper submission. We used the naive bayes classifier on the project and developed a method for adjusting the classification of datapoints depending on how exactly we want the classifier to perform, ie.... | g62802 | [
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0.008980181068181992,
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0.04387633502483368,
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0.07... |
<p>Can you tell me some procedures in R, which are able to find differentially expressed genes for a given microarray data?</p>
<p>Moreover,If you can give some ideas related to clustering of significant genes for microarray data, it will be quite helpful for me. </p> | g20060 | [
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0.020947232842445374,
0.04994499683380127,
0.0... |
<p>I want to use Lasso or ridge regression for a model with more than 50,000 variables. I want do so using software package in R. How can I estimate the shrinkage parameter ($\lambda$)? </p>
<p>Edits:</p>
<p>Here is the point I got up to:</p>
<pre><code>set.seed (123)
Y <- runif (1000)
Xv <- sample(c(1,0), siz... | g39210 | [
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0.02231561951339245,
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0.03915225714445114,
0.06743001192808151,
0.03178... |
<p>I am carrying out an evaluation for an intervention using secondary data. Unfortunately the design of the study is weak as participants cannot be randomised. I am looking to see whether the intervention has had any impact on patients quality of life? A measure of QoL has been taken before and after the intervention,... | g62803 | [
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0.0037575617898255587,
0.023649610579013824,
0.04009706899523735,
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... |
<p>Lets assume I have collected some data about sold ice creams on the local market on the daily basis. Days( just a number of observations, might be classified otherwise, it's not variable ) present the day collection of data took place, var1 represents sold ice creams between 09:00-10:00, var2 between 12:00-13:00, an... | g62804 | [
-0.010395989753305912,
0.029232364147901535,
0.0035080767702311277,
-0.029312988743185997,
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0.08034247905015945,
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-0.036201074719429016,
0.04574078693985939,
0.0008364346576854587,
0.04444025456905365,
... |
<p>I am build a model to predict the risk of having disease X, let say I have a series of variables and I select the variables to be included in multivariate logistic regression model by: i) clinical input and/or ii) p-value<0.25 in univariate regression.</p>
<p>I wonder if there will be an issue of collinearity if... | g20066 | [
-0.018458658829331398,
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0.016156157478690147,
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... |
<p>When I do a 2 (tasktype: slogan vs. product) x 2 (novelty: old vs. new) ANOVA, the interaction and the main effects do not seem to be significant. </p>
<p>But when I look at the pairwise comparisons, I see that old and new are significantly different from each other both in the slogan and product condition (p`s <... | g20069 | [
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<p>I am in need of a package that can give me the equation for a linear SVM model. Currently I'm using <a href="http://cran.r-project.org/web/packages/e1071/index.html" rel="nofollow">e1071</a> like so:</p>
<pre><code>library(e1071)
m = svm(data, labels, type='C', kernel='linear', cost=cost, probability=FALSE, scale=s... | g62805 | [
0.006738009862601757,
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0.0402863435447216,
0.03608686476945877,
0.010211583226919174,
0.07473303377628326,
0.03897073864... |
<p>I have a $10000\times2$ table (see below) where column <strong>A</strong> is made out of <em>observed data</em> and column <strong>B</strong> is the <em>output of a model</em> that I have which should fit the observed data <strong>A</strong>.</p>
<p>$n_{A}$ is the total number of points in column <strong>A</strong>... | g62806 | [
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0.02725575678050518,
0.02934211678802967,
0.005... |
<p>I have a numeric dataset involving 34 input variables and one output variable.</p>
<p>I'd like to fit a model to the data so to be able to make predictions (regression problem).</p>
<p>So far I've tested <code>MARS (Multivariate Adaptive Regression Spline, earth package), simple random forest (Random Forest, rando... | g62807 | [
0.03749392181634903,
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0.031036941334605217,
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<p>As the title goes, does anyone know of a good, up to date book that covers data preprocessing in general and especially outlier detection techniques?</p>
<p>The book doesn't need to be focusing exclusively on that, but it should deal with the aforementioned topics exhaustively - I wouldn't be happy with something t... | g39233 | [
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<p>I am working with some survey data that uses probability weights. A number of sources explain that likelihood-based tests and fit statistics like likelihood-ratio, AIC, and BIC <a href="http://www.stata.com/support/faqs/statistics/likelihood-ratio-test/">are not valid in the context of the weighted MLE</a>.</p>
<p>... | g10193 | [
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<p>In a multivariate regression, suppose we want to calculate the metric coefficients from the standardized ones. Is the method (standardized coeffcient times standard deviation of the dependent variable) valid in both OLS and IV or not?</p> | g62808 | [
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<p>What is the difference between Research Design and Experimental Design?</p>
<p>I can't see any difference. Both of them need to establish <em>Causality</em>.</p>
<p>Both of them are the arrangement for collection and analysis of data in a manner that aims to achieve the objective in an economical way.</p>
<p>Then... | g62809 | [
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<p>I am paving my way through Roger Nelsen's "An Introduction to Copulas".</p>
<p>The book has exercises (quite good actually), but no solutions.</p>
<p>Does anybody have a solution manual for (some of those) exercises?</p>
<p>Also references to Copula related (intro level) problem sets with solutions would be appre... | g5950 | [
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<p>Let's say I have an experiment with two factors <em>A</em> and <em>B</em>, each with a number of different levels. </p>
<p>I want participants to </p>
<ul>
<li>see all levels of factor <em>A</em> exactly $n$ times, </li>
<li>never see a level of <em>B</em> twice</li>
</ul>
<p>How would I generate a test plan that... | g62810 | [
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<p>I want to determine compliance to a certain standard in ISMS and to determine that, I have the standards started and it has sub-questions (say 2,3,4 questions), with each having a 5 point likert type choices. I have a sample of about 32 questionnaires filled. My difficulty now is how to treat or analyse the sub-ques... | g62811 | [
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<p>I have a few machines that are used to calibrate each other.</p>
<p>Machine 1 has is accurate to 0.025%</p>
<p>Machine 1 is used to calibrate Machine 2, which has an accuracy of 0.005%</p>
<p>Machine 2 is used to calibrate Machine 3, which has an accuracy of 0.025%</p>
<p>Machine 3 is used to calibrate Machine 4... | g20077 | [
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0.054630015045404434,
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<p>The question is probbaly easy, but I don't want to fool myself.</p>
<p>If there are three (univariate real) time series $A$, $B$ and $C$ such that $A$ and $B$ both highly correlated with $C$ at some arbitrary lags, does it implies that $A$ and $B$ also highly (<em>near</em> as high) correlated at some lag?</p>
<p>... | g62812 | [
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0.06366042792797089,
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<p>I'm wondering if my volatility factor is specified correctly. My data consists of log returns on the S&P 500 index, a measure of news sentiment, and a newscount variable (# of articles published on that day). Now I want to include a volatility variable, and I tried several but will explain my current issue.</p>
... | g62813 | [
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<p>If $X_i$ has a Beta distribution $\beta(1,K)$.</p>
<p>What is the best approximation for the distribution of $ S=\sum_{i=1}^N X_i$, when the $X_{i}$ are independent and $N$ is finite.</p>
<p>Thanks</p> | g62814 | [
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<p>I want to do clustering of my data in R, using kmeans or hclust (I am a new R user).</p>
<p>My data is ordinal, Likert scale, to measure the causes of cost escalation. I have 41 causes "variables" that scaled from 1 to 5 (1: no effect, 5: major effect). I have about 160 observations "who rank the causes".</p>
<p>I... | g39042 | [
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... |
<p>For a hypothesis $H_0\equiv p_1=p_2$ (for two Bernoulli distributions), we take a measurement and find that $X_1=i,X_2=j$, and we denote $k=i+j$</p>
<p>Now, to test $H_0$, the Fisher-Irwin test tells us to compute $$P_{H_0}(X_1=i|X_1+X_2=k)=\frac{\tbinom{n_1}{i}\tbinom{n_2}{k-i}}{\tbinom{n_1+n_2}{k}}$$</p>
<p>As I... | g20081 | [
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<p>How can I plot log likelihood function with type "I" Pareto distribution function $f(x|\alpha,k)=\alpha k^\alpha/x^{\alpha+1}$ in R? The problem for me is there are two parameters, how can I plot the log likelihood with two unknown parameters? Do I need to give a value of $\alpha$ and then plot the log likelihood f... | g20082 | [
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0... |
<p>What issues, if any, might there be in rotating factors in order to obtain factor/component loadings of binary data? Is it acceptable to rotate the factors when doing a traditional PCA? (Assuming I’m using a polychoric correlation matrix.)</p>
<p>I am not a statistician, but an applied educational researcher making... | g20083 | [
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<p>I am looking to understand the assumptions of using a generalized additive model.</p>
<p>1) Are the assumptions the same as the assumptions for each equivalent link function in a generalized linear model - e.g. as linear regression, logistic regression etc.
along with the assumption that the additive smooth struct... | g48567 | [
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<p>I'm doing a two sample z-test for the difference between means using pooled variance.</p>
<p>Suppose I've run two experiments. In the first experiment, the sample size for the two populations is only 100, and I get a z-value of 5.0. In the second experiment, the sample size for the two populations is one million,... | g37459 | [
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<p>If two or more variables A, B, C, etc. are jointly mutually independent of one another, does this imply that that they are also conditionally independent given some set of conditioning variables X, Y, Z, etc.?</p>
<p>If you test variables A, B, C,, etc., and the hypothesis of independence is not rejected, are you g... | g5984 | [
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<p>I am doing an ANCOVA model in order to explain the gap in a given distance. So I have a control group, and I have several quantitative variables, right now I am trying to evaluate the impact of the quantitative variables individually. But I think the results I get are incoherent, lest see:</p>
<pre><code> ... | g40336 | [
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0.007392493542283773,
0.005249653477221727,
0.018572667613625526,
0.018727155402302742,
... |
<p>I'm trying to generate random variables. I read about <strong>Box-Muller transform</strong> which is a way to generate a pair of normal variables, 2-d normal distrubution. But how do I expand that transform to generate 3-d, 4-d, etc. normal variables with this approach? Or is there a different approach to consider?<... | g62815 | [
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0.01608823984861374,
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0.021686799824237823,
-0.00... |
<p>In Poker, it is important to judge the likelihood of an opponents action, but for unknown opponents, we have few samples available. One method proposed in <a href="http://www.husng.com/content/interpreting-small-sample-sizes-bayesian-estimators" rel="nofollow">http://www.husng.com/content/interpreting-small-sample-s... | g4 | [
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0.008462014608085155,
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0.0016619309317320585,
0.016894342377781868,
-0.01636327989399433,... |
<h2>Question</h2>
<p>Suppose I observe a vector $\mathbf{x}=[X_1 \ldots X_n]$, where each $X_i=m_i+n_i$, with $n_i$ being an independent zero-mean Gaussian random variable with variance $\sigma^2$ (i.e. $n_i\sim\mathcal{N}(0,\sigma^2)$ i.i.d.) and $\mathbf{m}=[m_1 \ldots m_n]$ is an unknown vector with a known Euclide... | g44334 | [
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-0.028628427535295486,
0.03657731041312218,
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0.0014477791264653206,
0.026848196983337402,
0.027040798217058182,
0.03962970897555351,
0.00028465857030823827,
... |
<p>I am using the intraclass correlation coefficiant to determine inter-rater reliability for a set of pictures that were rated by several raters on a scale from 1-9.
I am using the two-way mixed model in SPSS and am interested in absolute agreement (rather than consistency). This works fine for all items (pictures) ta... | g20091 | [
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0.02867106907069683,... |
<p>I have a data set that has been collected by a set of empirical experiments. Having plotted them on a graph, it seems that the data behavior is linear. On the other hand, some colleagues claim that the data are not linear. How can I show them the confidence level of being linear for my data? In other words, is there... | g20092 | [
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<p>I am trying to regress (OLS) some time series on stock returns. I am not interested in regressing the returns of those time series on my stock returns, but I want to include information about the level (the higher the better) of these time series.</p>
<p>I read somewhere that the dependent variable has to be statio... | g20094 | [
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-0.03698383644223213,
0.02300206944346428,
0.05442226678133011,
0.01340373046696186,
0.022158... |
<p>I wanted to ask what is the best way to analyze proportion data with repeated measures. I will give a simple example.</p>
<p>Let's say you have a binary variable Y, which is a success/failure variable. You take a sample of n people.</p>
<p>In normal circumferences, you would count how many success you had out of n... | g62816 | [
0.0350019745528698,
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0.006136265117675066,
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0.01001258660107851,
0.0006501870229840279,
0... |
<p>was tasked with developing a regression model looking at student enrollment in different programs. This is a very nice, clean data set where the enrollment counts follow a Poisson distribution well. I fit a model in R (using both GLM and Zero Inflated Poisson.) The resulting residuals seemed reasonable.</p>
<p>Howe... | g62817 | [
0.027579041197896004,
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-0.03317785635590553,
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-0.001714071026071906,
0.017453154549002647,
0.009461293928325176,
0.010796225629746914,
... |
<p>I am specifically confused as to the meanings of the shaping and scaling parameters of the gamma distribution and how they are used in a real context. Once I find the correct parameters, I have the equations to find everything else I need.</p>
<p>The word problem that I am looking at is:</p>
<blockquote>
<p>Audr... | g62818 | [
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0.0454711876809597,
-0.024464696645736694,
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0.034711677581071854,
-0.015310178510844707,
-0.015499191358685493,
0.05000142380595207,
0.0175... |
<p>I am attempting to group, for example, strings about programming with other strings about programming, strings about physics with other strings about physics, etc., for a wide range of topics. Despite the glaring theoretical linguistic aspect of the problem, I am looking to actually do this using programming/softwar... | g20102 | [
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0.05457277595996857,
0.007172139827162027,
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-0.03128499165177345,
-0.017511898651719093,
-0.012424358166754246,
0.06685525923967361,
0.0436... |
<p>On the Wikipedia page for the <a href="https://en.wikipedia.org/wiki/Binomial_distribution" rel="nofollow">Binomial distribution</a>, the following property is mentioned (under the related distribution section): (paraphrased)</p>
<p>If $X\sim \text{Bin}(n,p)$ and $Y|X \sim \text{Bin}(X,q)$, then $Y \sim \text{Bin}(... | g62819 | [
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-0.045973993837833405,
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0.00595365883782506,
0.009062242694199085... |
<p>Let me explain my scenario in which I need to calculate absolute error.</p>
<p>Lets say the X is the actual value. And X' is the value of X with some error 'e'. So X' = X + e'.</p>
<p>Lets say i = 1 to 10000. I have X(i) as well as X'(i). Now I want to know (also want to plot on graph) that How much X' differs fro... | g62820 | [
0.015117147006094456,
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0.013843825086951256,
0.01685549132525921,
0.05920073390007019,
0.08580653369426727,
0... |
<p>Using R, I want to run a linear regression to estimate the abnormal return on days with positive, negative and neutral news (CLASS). I'm a beginner in R, as well as in using regression models!
First of all the data structure is as follows. CONTROLVAR just represents all the columns I use as control variables.</p>
... | g62821 | [
0.01622525230050087,
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0.006690004840493202,
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-0.04722386971116066,
0.03143515810370445,
0.03393397480249405,
0.03893623128533363,
0.0040... |
<p>I have a data set consisting of about 100,000 rows and two columns. The values in one column range from 0 to 10^9 the values in the other column range from 0 to 245. I've calculated the covariance between these two values and the result is 5x10^8. I realise this suggests two things:</p>
<pre><code>1) There is a cor... | g62822 | [
0.015902049839496613,
-0.002313579199835658,
0.0059016053564846516,
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-0.020954597741365433,
-0.002363833598792553,
0.016841167584061623,
0.010042104870080948,
-... |
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