question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Given a coin with unknown bias $p$, how can I generate variates β as efficiently as possible β that are Bernoulli-distributed with probability 0.5? That is, using the minimum number of flips per generated variate.</p> | g66504 | [
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<p>If I have a random variable $x$, and the only information I know about it are:
$$ m_1=E[x]=c, \mu_2=var(x)=0, \mu_3=E[(x-m_1)^3]=0$$
Can I conclude that the function distribution is symmetric about c?</p>
<p>Symmetric distributions have skewness = 0, and the definition of skewness in wikipedia is:
$$ \gamma = \frac... | g25535 | [
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<p>Lets say I have the following data frame</p>
<pre><code>library(survival)
library(multcomp)
data(cml)
cml$group<-sample(1:5, 507, replace=T)
plot(survfit(Surv(time=cml$time, cml$status)~factor(cml$group)))
(survdiff(Surv(time=cml$time, cml$status)~factor(cml$group)))
</code></pre>
<p>I want to perform multi... | g25536 | [
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<p>I am using the "metafor" package to do a multivariate meta-regression in "R". </p>
<p>I have 6 predictors and I am able to run the full model (all the predictors simultaneously in the model) just fine.</p>
<p>However, I would like to do a backward deletion meta-regression. I cannot figure out how to do it, and I a... | g769 | [
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<p>I obtain Figure 1, which shows the probability that a certain event will take place based on the <em>min threshold strain</em> (X-value). However, clearly the graph is hard to gather any info from. I then add up the probabilities in tiny intervals of the X-values. After that I divide each of the Y values by the sum ... | g66505 | [
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<p>I have been operating an online business for two years in a row now, so I have my monthly sales data for about two years. My business for every month is certainly affected by seasonal swing ( performs better at Christmas, etc), and probably some other factors that I am not aware of.</p>
<p>In order to predict futur... | g66506 | [
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<p>Let's say I want to generate $N$ sequences $p_j$, where $j = 1,\ldots,N$. Each sequence has a length of $M$. I want $\mathbb{E}[ p_j ] \to 0$ and $\text{corr}(p_j, p_k) \to \delta_{j, k}$ as $M \to +\infty$.</p>
<p>In practice, I can generate an $M \times N$ matrix of i.i.d. unit normals. For example, in MATLAB,... | g25538 | [
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<p>I am trying to determine the rate of cannibalization of product sales
for A with product B. I am using ~ 2 years of daily sales data
for product A and then ~8 months of data for product B. That is, product B
launched 8 month ago. I am using the longer series for A to capture
trend effects in the business (natural or... | g29392 | [
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<p>I am comparing models that I created with the lmer function from the lme4 package using ANOVA. Paricipants and verbs are my random factors, and RT are the Reaction Times that I measured. From the little statistics that I know, I would expect F-statictic values in the output, but instead I get chi-square.</p>
<p>Cou... | g66507 | [
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<p>This is a relatively simple question, but is not addressed in the documentation for the <code>ada</code> package in R. How do I go about instructing <code>ada()</code> to minimize specificity (instead of maximize accuracy)? I'm constructing a fraud detector (where only 1% of total orders are fraud) so it is impera... | g66508 | [
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<p>I'm using Weka to perform classification, clustering, and some regression on a few large data sets. I'm currently trying out all the classifiers (decision tree, SVM, naive bayes, etc.).</p>
<p>Is there an automated way (in Weka or other machine learning toolkit) to sweep through all the available classifier algorit... | g66509 | [
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<p>I am running cross-sectional regressions of the type</p>
<p>$$Y_c = \alpha + \beta X_1 + \gamma X_2 + \delta_1 X_3 + \delta_2 X_1 X_3 + \delta_3 X_2 X_3 + e_c.$$</p>
<p><strong>My theoretical model</strong> implies that </p>
<ul>
<li>$\delta_2$ should be negative, </li>
<li>$\delta_3$ should be positive, and</li>... | g25539 | [
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<p>Problem:<br>
What is a real life example of a power function? I tried thinking about it but I failed. Does somebody know?</p> | g49753 | [
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<p>Hello I need to compare the mean or median of a continuous but non-normally distributed variable between two groups, but also adjusting for some continuous and categorical covariates. I would think ANCOVA is what I need, except my variable is really skewed to the right, positive and with many zeros. I heard the Alig... | g66510 | [
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<p>Without going into specifics, I'm currently working on a system that involves 20-25 questions being answered as either Green, Yellow, Orange or Red. After completing a subset of these questions (many questions can be left as defaulting to Green), the system allows our users to choose one outcome out of four, roughly... | g66511 | [
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<p>I am trying to caculate survival function in a time dependent covariates Cox model from its baseline hazard function. However, my program gives a different result compared with <code>survfit</code>. Based on the formula </p>
<p>$S(t)=\exp(-\int_{0}^{t}\lambda_{0}(\mu)\exp[\hat{\beta}Z(\mu)]d\mu$</p>
<p>result sho... | g66512 | [
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<p>I'm studying a tutorial in a video about supervised learning, more specifically, it's about "linear regression with one variable", that is the cost function. </p>
<p>So my first question : <strong>is this "cost function" equal to "linear regression with one variable, or does "cost function" belong to linear regress... | g66513 | [
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<p>I'm calculating F- and p-values using the <a href="http://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.f_oneway.html" rel="nofollow">scipy.stats.f_oneway</a> ANOVA function and I'm having trouble interpreting the effect size f-values.</p>
<p>I'm getting numbers well above 100 in some cases, whereas from... | g25543 | [
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<p>I realize this question has been asked in various permutations (and I've reviewed the posts), but I can't find a good answer.</p>
<p>I have DVs that are 7-point Likert ITEMS. The items were presented horizontally with equal spacing 1 2 3...7 with verbal anchors corresponding to the bottom (1) and top (7) ends (disa... | g66514 | [
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<p>I read book "Data mining methods and models" by Daniel T.Larose chapter 1 for finding correlation in multidimensional dataset by PCA. The chapter explain theory well. I had implemented PCA algorithm in java and also extracted variables as you mentioned in book. </p>
<p>I have one concerned , I want to prioritize/ s... | g66515 | [
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<p>Is there a method out there that can compare the the KM estimate (i.e. survival proportion) at a specific time point (e.g. 5-year) across more than 2 groups? For example, a clinician would like to know if the survival probability at 5 years is different between groups. For groups = 2, the situation is simple in that... | g66516 | [
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<p>I am developing a questionnaire to measure four factors which constitute spirituality, and I would like to ask the following question: </p>
<p>Are data transformations on non-normal data necessary for an exploratory factor analysis when using the principal axis factoring extraction method?</p>
<p>I finished screen... | g49504 | [
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<p><strong>Background</strong>:
I have the cross-sectional model:</p>
<p>$Y_{i} = a + b X_{1,i} + c X_{2,i} + d X_{3,i} + e X_{4,i} + \nu_i$.</p>
<p>The application is corporate finance. So each $Y_i$ is something like the change in return on assets over a 1 year period for firm $i$, and the regressors are typical c... | g66517 | [
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<p>I was reading about parameter estimation techniques such as Maximum Likelihood Estimation(MLE) and Expectation Maximization(EM). I tried to derive the Maximum Likelihood Estimation formula for Markov Chain and I failed miserably. I, then, found a <a href="http://www.stat.cmu.edu/~cshalizi/462/lectures/06/markov-mle.... | g30197 | [
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<p>Suppose I want to make inference on a parameter vector $\theta $=$(\theta_{1},\theta_{2},\theta_{3})$ and I have some missing data $Y_{mis}$. I would like to use the EM algorithm to find the mode of the joint posterior $\pi (\theta_{1},\theta_{2},\theta_{3}|Y_{obs}) $ The EM algorithm would then dictate that given m... | g25553 | [
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<p>My first intuition was to use a t-test, but after looking in my memories and then in wikipedia I could not discern a conclusive answer... </p>
<p>In my course I want to talk about the rationale of the <strong>t-test</strong> in comparision to the <strong>chi-square</strong> (with which I compare the distributi... | g66518 | [
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<p>I was calculating a correlation between two variables (A and B) which revealed these variables are highly correlated. I know that one variable is also highly correlated with another one (C), therefore I did a partial correlation between A and B controlling for C. Now I receive a even higher correlation between A and... | g66519 | [
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<p>I am a bit confused on how to proceed using the MFA analysis from FactoMineR in my data set. I am currently working with activity results of 15 bacteria (b1, b2, b3, b4, b5,.., b15), divided into 3 groups (A, B, C); all groups were subjected to 4 different types of environmental treatments (heat, cold, pressure, UV)... | g35467 | [
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<p>Typically when I'm using Amos graphics I access my SPSS datafile and use individual items from a survey (observed variables) to make up my constructs (latent variables). In my current study, the aggregate score of one of my constructs was not normal distributed so I transformed it in SPSS (sqrt transformation). Beca... | g25557 | [
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<p>In this <a href="http://stats.stackexchange.com/questions/29719/how-to-determine-best-cutoff-point-and-its-confidence-interval-using-roc-curve-i">question</a>, one of the comments discusses the benefits of using Bayes optimum decision rules coupled with loss functions rather than using other performance metrics such... | g66520 | [
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<p>I have the following model fit:</p>
<pre><code>Call:
coxph(formula = surv ~ data$Arm * x)
coef exp(coef) se(coef) z p
data$ArmLevel1 0.062322 1.06 0.70338 0.0886 0.93
covariate1 -0.000495 1.00 0.00710 -0.0697 0.94
dat... | g66521 | [
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<p>I wanted to use some data for statistical analysis available on a company's website. The data is in the form of a time series. Am I allowed to publish my results and conclusions?</p> | g66522 | [
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<p>I have a group of 200 children who came to clinic at months 0, 1, 2, 3, 6, 9, and 12 this year. At each clinic visit the children were weighed.</p>
<pre><code># Set seed to create reproducible example data
set.seed(50)
# Create patient ID numbers, genders, and ages
control <- NULL
control$Age_0 = round(runif(20... | g25562 | [
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0.01... |
<p>The Wikipedia article on <a href="https://en.wikipedia.org/wiki/Principal_component_analysis">principal component analysis</a> states that</p>
<blockquote>
<p>Efficient algorithms exist to calculate the SVD of $X$ without having to form the matrix $X^TX$, so computing the SVD is now the standard way to calculate ... | g66523 | [
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<p>I have data from an experiment that I would like to analyse with a multilevel model. In the experiment, participants read 1 scenario about a person and they had to answer a couple of questions about this scenario. </p>
<p>The content of the scenario was determined by two between-subjects factors: income (high, low,... | g66524 | [
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<p>I am trying to analyse the effect of a treatment on the abundance of three response variables (either as absolute values, in which case they are counts with some zeros, or as relative proportions). Plots are stratified across 5 sites, each with 2 or 3 replicates of each of the 5 treatment levels. Each plot was sampl... | g25565 | [
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<p>I have two continuous variables $x_1$ and $x_2$, such that their sum is a constant: $x_1+x_2=c$. Clearly, I cannot run the following OLS model due to perfect multicollinearity:</p>
<p>Model (1): $y = \alpha + \beta_1 x_1 + \beta_2 x_2 + \epsilon$</p>
<p>If I run the Model (2) below, $\beta_1$ is significantly nega... | g66525 | [
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<p>I have read in the abstract of <a href="http://www.tandfonline.com/doi/abs/10.1080/00401706.1976.10489397">this paper</a> that:</p>
<blockquote>
<p>"The maximum likelihood (ML) procedure of Hartley aud Rao is modified by adapting a transformation from Pattersou and Thompson which partitions the likelihood render ... | g39531 | [
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<p>This has a simple answer but it has been eluding me nonetheless. </p>
<p>I have been trying to build a PCA plot from scratch with the ability to plot predefined groups in different colors. I can plot PCA but I want it to plot with predefined groups (samples) with top 100 expressed genes. I have three groups. Can a... | g45891 | [
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<p>I hope you all don't mind this question, but I need help interpreting output for a linear mixed effects model output I've been trying to learn to do in R. I am new to longitudinal data analysis and linear mixed effects regression. I have a model I fitted with weeks as the time predictor, and score on an employment c... | g66526 | [
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<p>My data is discrete and has the following distribution:</p>
<p>P(1) = 0.45, P(2) = 0.5, P(3) = 0.02, P(> 3) = 0.02</p>
<p>I want to remove outliers systematically, given the distribution and the fact that 1 is the lower bound. When I apply Tukey's 1.5 IQR rule and mean +- 2*sd rules, they both result in 3 being i... | g66527 | [
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<p>I am working on a project that collected data retrospectively on subjects. There are subjects with multiple points of follow up per person, anywhere from 1 to 3 measurements. The timing of such measurements is extremely variable. Most subjects have 1 measurement, but many have 2 or 3. We are interested in the po... | g25572 | [
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<p>In my data I have an outcome - "daily satisfaction" - measured on a 1 to 5 scale with 5 representing the respondent was very satisfied with her day and 1 representing the respondent was very unsatisfied with her day. I also have information on what a respondent did that day, e.g., visited a museum, listened to music... | g66528 | [
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<p>I am not sure how to proceed with this CFA im doing in lavaan. I have a sample of 172 participants (I know thatβs not much for a CFA) and 28 items with 7-point Likert scales that should load on seven factors. I did a CFA with βmlmβ-estimators, but the model fit was really bad (Ο2(df=329)=739.36; comparative fit inde... | g66529 | [
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<p>I am a R beginner. Is there a way to specify custom error function with Random Forests in R? For example, say my training data is ,,, so on and my error for any given set needs to normalize the weights and then calculate the mean of absolute error. So my error for each data point is <code>(predicted-actual)*normaliz... | g45899 | [
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<p>I'm using the Poisson distribution to predict the number of concurrent users accessing a website. The method is described in a <a href="http://wenku.baidu.com/view/68f1853a580216fc700afd74.html" rel="nofollow">paper by Eric Man Wong</a>.</p>
<p>This paper provides a formula for calculating the average number of con... | g66530 | [
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<p>I once read the following inequality </p>
<p><img src="http://i.stack.imgur.com/Wx8rr.png" alt="enter image description here"></p>
<p>Is there any specific name for this inequality? And, how to prove it?</p> | g66531 | [
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<p>I am trying to perform a Pearson's chi-square goodness of fit test on my Generalized Linear Model to measure how well the model fits my data. </p>
<p>Below is my code:</p>
<pre><code>m1.pearson <- residuals(m1, type = "pearson")
pchisq(sum(m1.pearson^2), m1$df.residual)
</code></pre>
<p>My question is: if t... | g66532 | [
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<p>So, far I have read following regarding boosting:</p>
<ul>
<li>Boosting is an ensemble technique. </li>
<li>Train learner sequentially, where early learners fit simple models to the data.</li>
<li>Analyze data for errors, that is, focus on records that have high errors and try to get them right. </li>
<li>In the en... | g66533 | [
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... |
<p>When assessing the performance of an estimator, in which scenarios should one prefer the use of the <strong>Mean Absolute Deviation Error</strong> (MADE) over the <strong>Mean Squared Error</strong> (MSE) and vice versa?</p>
<p>Edit / Clarification:</p>
<p>Assume that we have i.i.d data $(X_{1},Y_{1}),\cdots,(X_{n... | g66534 | [
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<p>$$
r = \frac{{\rm Cov}(X,Y)}{ \sigma_{X} \sigma_{Y}}
$$
I do not understand this equation at all. Where does it come from? </p>
<p>From my personal understanding ${\rm Cov}(X,Y)$ comes from that fact that $X$ and $Y$ are dependent random variables, that is, $E[XY]$ is not the same as $E[X]E[Y]$. Is this analogous t... | g66535 | [
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<p>I'm trying to replicate <a href="http://www.mendeley.com/research/averaging-correlation-coefficients-should-fishers-z-transformation-be-used/" rel="nofollow">Silver & Dunlap (1987)</a>. I'm just comparing averaging correlations or averaging z transform correlations and back transforming. I seem to not be repli... | g25575 | [
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<p>I would like to compare data among different sets where the values span the same range (0,1] but will have different means and unknown distributions. Given the unknown distributions, I thought of applying bootstrap to estimate distribution paramaters, but my problem comes at how to standardize across sets. The way, ... | g66536 | [
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... |
<p>Does anyone know of an R package that computes upper and lower bounds for a coefficient of variation? Preferably using one of the methods described under distribution here:</p>
<p><a href="http://en.wikipedia.org/wiki/Coefficient_of_variation#cite_note-13" rel="nofollow">http://en.wikipedia.org/wiki/Coefficient_of... | g66537 | [
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<p>I'm a pharmacologist and, in my experience, almost all papers in basic biomedical research use Student's t-test (either to support inference or to conform to expectations...). A couple of years ago it came to my attention that Student's t-test is not the most efficient test that might be used: sequential tests offer... | g25577 | [
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<p>i am working with a set of distributions. I have so far analyzed several probability distributions with respect to each other, that means i have made a t-test, to see how probable it is that two events happen at the same time according to those distributions.
That means i have computed:</p>
<pre><code>let x1 and x2... | g40352 | [
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<p>Below is part of the proof of large deviations result. K is cumulant generating function. Can anyone explain how the last step follows? </p>
<p><img src="http://yaroslavvb.com/upload/large-dev.png"></p>
<p>This is page 157 of McCullagh's "Tensor Methods in Statistics"</p> | g45915 | [
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<p>Suppose you have an $n$-vector $X$. For a fixed real number, $r$ between $-1$ and $1$, can one generate a random permutation of the integers $1,2,\ldots,n$, call it $i_1,i_2,\ldots,i_n$ such that the vector $X$ and the vector $\tilde{X}$ defined by $\tilde{X_j} = X_{i_j}$ have expected sample correlation of $r$? I ... | g49925 | [
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... |
<p>I'm currently running a perception experiment: </p>
<ul>
<li>DV: error (this in degrees- how much an observer was away from the real answer) </li>
<li>IV: the time bin (5 levels) in which the unique stimulus appeared</li>
<li>IV2: True/False- whether the unique stimulus occurred before or after stimulus2. </li>
<li... | g66538 | [
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0.... |
<p>I have collected biometric data on two stimuli (they are TV ads). The output is a second by second response, with values from $0$ to $1$. I want to know whether the peak response from one ad is higher than the peak response from the other. What is the appropriate test to perform to determine whether the difference i... | g66539 | [
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<p>Hellow I need to know what the difference between a pairwise t-test and a pairwise ANOVA is. Preferably explained in laymen terms.</p> | g25585 | [
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... |
<p>I have this function $P = f(\alpha)$. $\alpha$ is a function $\alpha = f(\theta, x)=\theta x$. Now I have</p>
<p>$P = \alpha(x_1+x_2 + ...x_n)$</p>
<p>Now I need to calculate the partial derivative of P wrt $\theta$. Then</p>
<p>$\frac{\partial P}{\partial \theta} = \frac{\partial P}{\partial \alpha} * \frac{\par... | g771 | [
0.0007879345212131739,
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0.036... |
<p>If the residuals show that the non constancy of the error variance is clearly present, does it mean that your regression results are completely invalid?</p> | g25588 | [
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<p>I just wanted to do this small experiment to make sure I understand PCA correctly. My dataset contains 8 columns. The first two columns are randomly generated in excel => randbetween(4, 5) and the other 6 columns are also generated in the same way but the formula used is => randbetween(1,3)</p>
<p>When I do PCA on... | g2816 | [
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0.0... |
<p>I'm interested in hearing about what statistics problems other data teams are trying to tackle. For me, I have data on energy usage in the United States, and we are trying to figure out ways to forecast energy demand as well as figure out ways to balance heavy loads on the power grid. The statistical challenges ar... | g25590 | [
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<p>Local linear regression is a popular tool. How can one choose the number of grid points for which to estimate the unknown function on?</p> | g66540 | [
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<p>I am currently working on convergence proof for a new method for non-parametric importance sampling, and I need some help...</p>
<p>My method uses an MCMC algorithm to generate a set of dependent $M$ samples $X_1 \dots X_M$ from a distribution $g$, and then reconstructs an approximation of this distribution $\hat{g... | g66541 | [
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0.0460209995508194,
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<p>I am looking at the repeated cross-sectional data from federal reserves, which has both panel data and repeated cross sectional data at different time-points,e.g. 2007-2009 is a panel while 2010 is a cross sectional data set and everything before that is repeated cross section as well until you get back to the 1983-... | g25592 | [
-0.0015767201548442245,
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... |
<p>I am doing some forest disturbance research, in which the aim is to predict the probabilities of wind damage occurrence in forest stands of different site (altitude, slope steepness) and stand properties (age, timber volume).
I am using a logistic regression (because of the binomial response variable: 0-1) with the ... | g66542 | [
0.027457062155008316,
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0.009919196367263794,
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0.007276496849954128,
0.03970538452267647,
0.0463472455739975,
0.009728310629725456,
-0.03... |
<p>A simple example is given below:</p>
<pre><code>mat <- diag(1:6)
qr.R(qr(as(mat,"Matrix")))
qr.R(qr(dd))
</code></pre>
<p>the diagnal values are of opposite signs. There is a warning message when doing sparse QR decomposition:</p>
<pre><code>Warning message:
In qr.R(qr(as(dd, "Matrix"))) :
qr.R(<sparse>)... | g66543 | [
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<p>In my panel data I observe a quite large amount of different individuals for a fixed time duration. The time axis is fixed for every individual, i.e., I observe 20 time points for every individual.</p>
<p>The dependend variable is of kardinal scale but I choosed to transform it into ordinal scale. The reason for th... | g39456 | [
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<p>How can I, after running multivariate linear regression, compute the Generalization Error (also known as Test Error)? Are there many practises to do that?</p>
<p>EDIT: Can the following be considered as Generalization (or Test) Error?</p>
<pre><code>y = data1; [M,N] = size(y);
X = [ones(M,N) data2];
y_train = y(M-... | g2873 | [
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<p>I am running a moderation analysis using hierarchical linear regression. I have two predictor variables and two moderating variables and I am interested in their interactions to predict an outcome. My analysis includes the four possible interaction terms, but I am only theoretically interested in two - is it ok to l... | g66544 | [
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<p>I would like to apply one or more data mining techniques to a dataset, in order to see the effect advertising has on sales. </p>
<p>I am working from this <a href="http://datamarket.com/data/set/22kw/advertising-and-sales-data-36-consecutive-monthly-sales-and-advertising-expenditures-of-a-dietary-weight-control-pro... | g66545 | [
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0.06343457847833633,
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-0.... |
<p>I am using a logistic regression model to predict a binary decision (purchase, don't purchase) based on several independent variables (income, age, education, etc.) for a population of individuals (customers). I have data for individuals from one or more previous time periods, and I want to predict behavior for dif... | g66546 | [
-0.028597375378012657,
0.033182717859745026,
0.01936563476920128,
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0.013181805610656738,
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0.05885319411754608,
0... |
<p>I am Pradeep pursuing M.tech at S.I.T, Tumkur, India. I have stuck in a problem while implementing Deep Belief Networks for Isolated Word Recognition. The procedure i have adopted is described below, please do help me in analysing the stage where i went wrong.</p>
<p>Back-propagation algorithm implementation :
The ... | g66547 | [
0.016718069091439247,
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0.013105264864861965,
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0.010805643163621426,
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0.10908974707126617,
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0.0... |
<p>After taking my first semester stats class I started getting more and more into statistics. Currently I've come across this version of the Pearson Correlation Coefficient. Comparing this formula to the formula presented on Wikipedia shows they're inconsistent. Further, I've seen at least 3 different ways to calculat... | g66548 | [
0.04169300198554993,
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0.022436102852225304,
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0.0... |
<p>I'm looking for a statistical test which tells the probability that a given sample comes from a uniform distribution.</p>
<p>Shapiro test wether a sample comes from a normal distribution. I'm looking a similar test which test wether a sample comes from a uniform distribution.</p>
<p>Thank you</p> | g45937 | [
0.04530317708849907,
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0.038661908358335495,
0.008290900848805904,
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<p>I am performing a study in which i want to analyze the relationship between software project metrics.
In each project, there is a population of software modules. For each module, I compute the values of two software metrics A and B.</p>
<p>I want to compute rank correlation between the two metrics A and B, and I am... | g28314 | [
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<p>In this <a href="http://stats.stackexchange.com/questions/55168/one-step-ahead-forecast-with-new-data-collected-sequentially">post</a> it was asked how to do one step ahead forecasts using Arima form the forecast package. Now I'm using an example with hourly seasonal data and would like to do something similar but t... | g45068 | [
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0.014359571039676666,
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0.02625995688140392... |
<p>More precisely I mean "<em>All other things being equal</em>, what impact does including more predictors ('IVs') have on the CI for R squared?"</p>
<p>Say we'll get an R squared of .30 no matter whether we include 4 predictor variables or 7 predictor variables. Would one definitely produce a more precise CI than th... | g25602 | [
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<p>Suppose in a given experiment that an event $E$ will occur with probability $p$; if the experiment is staged only once, then we know from the previous statement that the probability that the event $E$ occurs is given by $p$.</p>
<p>Now, say we stage the experiment $n$ times (where $n \to \infty$ and experiments are... | g66549 | [
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<p>Lets say you have a class $C$ of binary strings $s$, and each string corresponds to one of $n$ categories. How do you quantify the complexity of the relationship between the sequence of bits in $s$ and the categorization of $s$.</p>
<p>For example, Imagine your strings are 6 bits long, $n=2$, and the first bit is t... | g25604 | [
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<p>I am confused on why a simple trend process is not stationary. Consider the following process:</p>
<p>$Y_t = a + bt + \epsilon_t$</p>
<p>The variance is clearly constant. However, the mean $bt$ is dependent on $t$. When shifted in time, the mean only depends on the time interval and is independent of history. For ... | g25606 | [
0.0543835423886776,
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<p>Is there a way to type in a regression formula in SPSS in the same manner as R, with weights?</p>
<p>For example, in R, I would write something like: </p>
<pre><code>lm(y ~ B1 + B2 + B1*B2, data=df, weights=x)
</code></pre>
<p>How would I go about recreating this in SPSS/PASW? </p> | g45950 | [
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<p><strong>Context:</strong>
In response to an earlier question about reproducible research <a href="http://stats.stackexchange.com/questions/1980/complete-substantive-examples-of-reproducible-research-using-r/4459#4459">Jake wrote</a></p>
<blockquote>
<p>One problem we discovered when
creating our JASA archive wa... | g45951 | [
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<p>I am a student, working with a team on a large-scale ecological experiment. We want to analyze survival data which has been derived from an experimental design with some pseudo-replication. This pseudo-replication was not discovered, unfortunately, until the middle of the experiment, at which point the design could ... | g66550 | [
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<p>I do a bunch of Real Estate Reporting and the Median price is often reported. Particularly by the NAR (National Association Of Realtors) ,,, How can this be,, As best I can figure they only get the Medians from each area,, so how should they calculate a national median, a median of medians a a simple average of medi... | g66551 | [
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<p>I'm in the process of analysing different PHP frameworks and part of this involves testing the load times. For this, I've programmed various usage scenario's. I'm however quite unsure on how to proceed from this. </p>
<p>I'm using Apache Benchmark to simulate the number of requests and the number of concurrent requ... | g66552 | [
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<p>I am interesting in simulating AR(1) processes with 0.9 parameter and n = 10. The itterations should be 10000.
When I was trying to run the program it gave me an error in the estimation procedure. </p>
<p>"Error in arima(newyt, order = c(1, 0, 0)) :
non-stationary AR part from CSS "</p>
<p>My code is this:</p>... | g66553 | [
0.010477053932845592,
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0.05499524250626564,
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0.034218769520521164,
0.0050... |
<p>I have carried out this ANOVA:</p>
<pre><code>summary(aov(drat ~ cyl, mtcars))
Df Sum Sq Mean Sq F value Pr(>F)
cyl 1 4.342 4.342 28.81 8.24e-06 ***
Residuals 30 4.521 0.151
---
Signif. codes: 0 β***β 0.001 β**β 0.01 β*β 0.05 β.β 0.1 β β 1
</code></pre>... | g66554 | [
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<p>I am running LDA from <a href="http://psiexp.ss.uci.edu/research/programs_data/toolbox.htm" rel="nofollow">Mark Steyver's MATLAB Topic Modelling toolkit</a> on a few Apache Java open source projects. I have taken care of stop word removal (for e.g. words such Apache, java keywords are marked as stopwords) and tokeni... | g25610 | [
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-0.04932621866464615,
0.01256090309470892,
-0.03452194482088089,
0.011474734172224998,
0.058... |
<p>I want to understand <a href="http://www.google.co.ve/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCYQFjAA&url=http://people.csail.mit.edu/menze/papers/menze_10_generative.pdf&ei=kKxSULuOFo-C8ASaq4GADQ&usg=AFQjCNHvGj6fo8fvScCTK5vd2IjsOwXyAg&sig2=q0MyFzQ1r9awzT-sR... | g66555 | [
0.017162222415208817,
-0.0007743947207927704,
-0.017888953909277916,
-0.05011491850018501,
0.033093374222517014,
0.02148716151714325,
0.053612321615219116,
0.03942269831895828,
-0.046064719557762146,
0.002233917359262705,
0.02004760131239891,
0.0003635379543993622,
0.08298978209495544,
-0.... |
<p>Why Beta process is useful/important? How different is that from Dirichlet process? </p> | g25612 | [
0.027978595346212387,
0.0038011895958334208,
0.024284852668642998,
0.007142175454646349,
0.043298784643411636,
-0.008036868646740913,
0.030933599919080734,
0.013074790127575397,
-0.025036312639713287,
-0.059341996908187866,
-0.038714129477739334,
0.037937842309474945,
0.04861579090356827,
... |
<p>I have a data set which contains a hundred or so user <strong>tags</strong> - that is, binary variables marking whether a user has a certain property or has shown a certain behaviour. (data from a web site.)</p>
<pre><code>user, high_usage, tablet, likes_cats, night_owl
A, 1, 0, 1, 0
B, ... | g66556 | [
-0.04616051912307739,
0.06515293568372726,
-0.009953230619430542,
-0.05692414566874504,
0.02613624557852745,
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-0.0010312350932508707,
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-0.05186709016561508,
0.01088026911020279,
0.03891352191567421,
0.06014531850814819,
0.051... |
<p>Both <strong><em>box-and-whisker</em></strong> plot and <strong><em>bar chart</em></strong> are appropriate graphics
for ANOVA according to The R Book (Crawley, 2013),
but <strong>which is more appropriate</strong>? I suppose it depends on situation... can anybody help me?</p> | g66557 | [
-0.005318542011082172,
0.04138467460870743,
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0.015854721888899803,
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0.004323164466768503,
0.08729132264852524,
0.029559191316366196,
0.059239596128463745,
0.0... |
<p>The following sounds like a very basic question in learning theory to me, so I am hoping someone can point out the obvious.</p>
<p>Efron's "expected optimism" is the expected difference between the prediction and training errors. Efron (2004) shows that for a wide range of loss functions (the "q-family"), and virtu... | g25615 | [
-0.021690262481570244,
-0.01249020453542471,
0.01763957180082798,
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-0.04644886031746864,
0.007350982166826725,
-0.0016213285271078348,
0.07456041127443314,
0... |
<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/1142/simple-algorithm-for-online-outlier-detection-of-a-generic-time-series">Simple algorithm for online outlier detection of a generic time series</a> </p>
</blockquote>
<p>How could I get rid of sparky d... | g49496 | [
0.03276064991950989,
-0.02326788194477558,
-0.01616450771689415,
-0.07998106628656387,
0.014481227844953537,
-0.05109477415680885,
0.02292928472161293,
0.020513182505965233,
-0.058666083961725235,
-0.007517712656408548,
-0.06197382137179375,
0.042113564908504486,
0.017919257283210754,
-0.0... |
<p>I am current using the package (lme4) for a mixed effect model with random effects.</p>
<p>My model takes the form:</p>
<pre><code>mod <- lmer(response ~ b1(predict1, bp) + b2(predict2, bp) + (1 | site), data = data)
</code></pre>
<p>The functions b1 and b2 come from the helpful advice in:</p>
<p><a href="htt... | g25619 | [
-0.02572743594646454,
-0.07815427333116531,
-0.01789630949497223,
-0.03450945392251015,
0.04274158179759979,
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0.017047131434082985,
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-0.020595790818333626,
-0.053913116455078125,
0.016101673245429993,
-0.0015544972848147154,
... |
<p>I am training a neural network with time dependent financial data. In order to avoid overfitting I would like to stop the training at the point where my neural network stops improving on a set of validation data, different from the training data. </p>
<p>My question is how to best divide my data in training and val... | g42811 | [
0.03258565068244934,
0.014986680820584297,
0.010435345582664013,
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0.0012349707540124655,
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0.02648165263235569,
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-0.014199834316968918,
0.031155092641711235,
0.029276210814714432,
0.005280958954244852,
0.01... |
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