question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Are any weights supplied to <a href="http://cran.r-project.org/web/packages/glmnet/index.html" rel="nofollow">glmnet</a><code>::cv.glmnet</code> taken into account for the calculation of the figure of merit (AUC for logistic regression in my case) on the "held-out" dataset, or only used directly in the fitting?</p> | g20758 | [
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<p>One common thing to do when doing Principal Component Analysis (pca) is to plot two loadings against each other to investigate the relationships between the variables. In the paper accompanying the <a href="http://www.jstatsoft.org/v18/i02" rel="nofollow">pls R package</a> for doing Principal Component Regression an... | g63200 | [
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<p>Unfortunately for me, I've got a situation where I need to control for the lag of a dependent variable as a robustness check against an alternative interpretation of my main regression. The baseline specification is
$$
y_{it} = \alpha_i + \delta y_{i,t-1} + X'\beta + \epsilon_{it}
$$</p>
<p>The lagged dependent v... | g63201 | [
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<p>I am currently using a Bayesian network model with 20 variables and 210 data points, with 15 locations measured at 14 different time points each. There are also some restrictions on what types of connections are allowed.</p>
<p>I have looked at <strong>leave-one-out cross-validation</strong> methods (and arguably l... | g20762 | [
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<p>I do not want to say my AUC is 0.77 and find out I am overlooking a lot. Below is my code and a two question at the bottom:</p>
<pre><code>setwd("g:/docs/Model")
mydata <- read.csv("TModel_JUL16.csv")
summary(mydata)
mydata$ZIP <- factor(mydata$ZIP)
mydata$RACE <-factor(mydata$RACE)
mydata$GENDER <-fact... | g63202 | [
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<p>I received this question for a Statistics / Machine Learning assignment and I'd like to you if any of you know the proper answer.</p>
<p>If we have n data points, what is the probability that a given data point does not appear in a bootstrap sample?</p>
<p>Sounds simple enough right? I'm reading Introduction to St... | g49666 | [
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<p>I'm using two 3-layer feedforward multi-layer perceptrons (MLPs). With the same input data (14 input neurons), I do one classification (true/false), and one regression (if true, "how much")¹.
Until now, I've lazily used Matlabs <a href="http://www.mathworks.se/help/nnet/ref/patternnet.html" rel="nofollow">patternne... | g63203 | [
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<p>I have some confusion related to the dual function or the Lagrangian being concave
for a general convex optimization problem with objective function $f_0(x)$ and equality and non equality constraints given by $h_j$ and $f_i$</p>
<p>$$
g(\lambda, \mu) = \text{inf}_{x \epsilon D} L(x,\lambda,\mu) = \text{inf}_{x \eps... | g63204 | [
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<p>I am trying to calculate the required (unstandardized) difference in between a test and control group of different sizes. I have historical data with transactions for </p>
<ul>
<li>the test group (n=272, mean transactions = 63.21, sum of transactions = 17194) </li>
<li>the control group (n=831, mean transactions = ... | g20764 | [
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<p>WinBUGS comes with the GeoBUGS add-on, which contains a number of predefined model structures that are suitable for modelling spatial data structures e.g. geostatical structures (spatial.exp), conditional auto-regressive, CAR, structures (car.proper, car.normal) amongst others. Unfortunately there are no comparable ... | g63205 | [
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<p>I have this question in my textbook I am having trouble answering. </p>
<p>You have a fleet of 19 vehicles, 4 of which are vans and 15 of which are cars. Say you need to choose two vehicles at random. Regardless of which vehicle you choose first, what is the probability that second vehicle you choose is a van? </p>... | g63206 | [
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<p>I have been working on this problem for the last little while and trying to write out the code to the below math/description for an ecological dataset in <code>lmer</code>, but I wanted to check with a few people to see if the code I've written out adequately reflects the math (which I am certain of!), as I could no... | g63207 | [
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<p>I am testing whether price per ounce of beer (continuous variable, range of values mostly between 0.1 and 0.5 dollars) and the presence of promotion, advertisement, and display (all binary) have effect on the total amount of ounces purchased (continuous variable).
Here is my residual vs. fitted plot before the log t... | g20767 | [
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<p>I have a question about how I can analyze the data from a time series experiment. I'm still a student and therefore am not really familiar with all the procedures and analyzes in SPSS, so i hope someone with the proper knowledge can help me with this problem. </p>
<p>The goal is to show a relation between advertisi... | g20768 | [
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<p>Suppose I bootstrap the distribution of the sample mean. Normally, one would use the mean of the bootstrapped distribution as point estimate of the parameter and the s.d. as its standard error. The mean of the bootstrapped distribution is asymptotically equal to the sample estimate (i.e. for a large number of iterat... | g63208 | [
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<p>I hope somebody can help me with this. I estimated vector error correction model (and Johansen's cointegration test) and my R-squared is only 23%. Does R-squared tell me my model is bad in this case too?</p> | g20770 | [
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<p>I have a classification problem (bioinformatics domain) where I have around 333 features. Currently, I am first selecting features (using importance feature of random forest) and then pushing the same through RBF kernel for SVM. On the results front, I have section of data which gives bad results on the classifier.
... | g20771 | [
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<p>I have discussed this issue several times in this site, but I am asking it again for a final justification from the experts of our community. I wanted to extract four factors (I should call dimensions here I think) from a CATPCA along with the factor scores (note that, factor scores are not available if I use polych... | g63209 | [
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<p>I have some questions about the AIC and hope you can help me. I applied model selection (backward, or forward) based on the AIC on my data. And some of the selected variables ended up with a p-values > 0.05. I know that people are saying we should select models based on the AIC instead of the p-value, so seems that ... | g20773 | [
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<p>Based on this very good post <a href="http://stats.stackexchange.com/questions/18603/how-can-i-calculate-margin-of-error-in-a-nps-net-promoter-score-result">How can I calculate margin of error in a NPS (Net Promoter Score) result?</a> I've pulled together the detailed calculations to perform the test for the general... | g63210 | [
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<p>We have several weather files for a year's data sampled hourly. In each we have several variables (up to ten), temperature, wind speed, solar intensity etc.</p>
<p>I would like to try and develop a system that could determine if these files are statistically different. If I was using a single variable, I could use ... | g63211 | [
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<p>I have a logistic regression model with several variables and one of those variables (called x3 in my example below) is not significant. However, x3 should remain in the model because it is scientifically important.</p>
<p>Now, x3 is continuous and I want to create a plot of the predicted probability vs x3. Even th... | g63212 | [
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<p>I have 2 real and 1 discrete input variable whereas the output variable takes either of the 2 nominal values (i.e. 2 class problem). First I used Weka to train C 4.5 decision tree in a 10-fold cross validation setup. As a result I get a single decision tree whose True positive, False positive rates don't change much... | g63213 | [
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<p>Motivated by my answer to <a href="http://stats.stackexchange.com/questions/69130/how-to-get-pooled-p-values-on-tests-done-in-multiple-imputed-datasets">this question</a>, I played around with analyzing mulitply imputed data from the <code>Amelia</code> package in R. As I have explained in my answer, the multiply im... | g63214 | [
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<p>I am aware of extreme value theory for continuous distributions. I need to fit an extreme value distribution to the maximum observation of number of events on a day, per month. This seems to be the block maxima problem, which is approximated by the GEV family of distributions for continuous distributions. How do I ... | g63215 | [
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<p>I have approximately 500,000 data points that were mechanically measured over about 2000 days. The equipment is manually set up each day, which likely induces some error. What I am attempting to do is use a linear mixed effects model to estimate the fixed effect of each day's potential measurement error while acco... | g63216 | [
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<p>I am trying to derive ELM going through the basics , please help me out here : </p>
<p>$$f = x^Tx$$
$$g = Ax-b $$ </p>
<p>The constraint is $Ax-b = 0$</p>
<p>I calculated $J' = f'+\lambda^T g'$
which is $2x+(\lambda^T A)^T = 0 $ and $Ax-b=0$ .
I dont know what to do next please help me out .</p> | g49667 | [
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<p>My problem is I have 3 biological replications (reps) withe each having 4-5 technical reps with two of the biological reps having comparable results for the treatment and control. </p>
<p>These values represent the colonization of donor stem cells. (Treatment is about 50% of control) whereas in the third rep I sti... | g20786 | [
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<p>Let's assume I have 10 users who rank a list by preference.</p>
<ol>
<li>A</li>
<li>B</li>
<li><p>C</p>
<p>etc.</p></li>
</ol>
<p>My questions are:</p>
<ol>
<li>What is the best statistical method to find which lists are the most correlated? If they are the same, 100% correlation, or 1 item switched with another... | g20787 | [
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<p>Is it possible to test the following? Assume you have two linear regression models, one regressing $Y_1$ on $X_1$ the other $Y_2$ on $X_2$. This gives error variance $\sigma_1^2$ and $\sigma_2^2$. From a sample all variables are available. I would like to evaluate $$H_0: \sigma_1^2=\sigma_2^2,$$ or one-sided $$H_0: ... | g63217 | [
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<p>I am using a GLMM to model the probability of visiting a 400m radius area. I have 135,000 observations (areas) and for each area I have the proportion of the habitat types within it. I want to examine the effect of habitat type on probability of visitation. However, I have split the habitat types into whether they a... | g63218 | [
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0.0070626139640808105,
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0.02430065907537937,
0.001... |
<p>Suppose we measure the classifier error on a test set and obtain a certain success rate - say, 75%. Now, of course, this is only one measurement - how to calculate the "true" success rate? Sure it will be close to 75% but how close? </p>
<p>I understand it's related to confidence intervals but now I'm lost in confi... | g63219 | [
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<p>A <a href="http://en.wikipedia.org/wiki/Recommender_system">Recommender System</a> would measure the correlation between ratings of different users and yield recommendations for a given user about the items which may be of interest to him.</p>
<p>However, tastes change over time so <em>old ratings</em> might not re... | g49668 | [
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<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/20010/how-can-i-help-ensure-testing-data-does-not-leak-into-training-data">How can I help ensure testing data does not leak into training data?</a> </p>
</blockquote>
<p>Overfitting is obviously a signific... | g49669 | [
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... |
<p>The formula of Cook's distance is
$$D_i=\frac{(\hat Y-\hat Y(i))^{\prime}(\hat Y-\hat Y(i))}{p\times MSE}$$</p>
<p>where,
$\hat Y$ is the prediction from the full regression model and $\hat Y$ is a $(n\times 1)$ matrix</p>
<p>$\hat Y(i)$ is the prediction from a refitted regression model in which observation $i $... | g9840 | [
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<p>I need an equation for random forest so that I can score fresh data I receive every week, based on beta estimates I got after building model using this ensemble methodology. </p>
<p>Every week I do not want to build random forest model again and then score it using following commands in Python. Because I have build... | g63220 | [
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<p>This might come as a very trivial thing and way below standards of this group but I am struggling to figure out what do the authors mean when they say that they have used initial level of income in growth regressions? assuming that the first obervation in the sample is 120, is it something like this:<br/></p>
<p>Ye... | g20795 | [
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<p>I'm running an A/B test where I want to compare two different layout of a button and want to see if one layout lead to a higher Click-Through Rate with a certain statistical power. I want to use a significance level of 0.05. </p>
<p>Layout 1 has 25302 visualization and received 40 clicks.
Layout 2 has 27924 visuali... | g20796 | [
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<p>I have a question about how to do analysis of an experiment that has already been done, I hope you can help me with some advice!</p>
<p>I will try to keep it as simple as possible, but will give some detail so you know what I'm talking about!</p>
<p>What has been done is a "screening trial" to look at the activity... | g63221 | [
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<p>I modified the following script for Optics clustering ( <a href="http://chemometria.us.edu.pl/download/OPTICS.M" rel="nofollow">http://chemometria.us.edu.pl/download/OPTICS.M</a> ) in order to work with DTW distance instead than Euclidean's.</p>
<p>I obtained the Order vector (order), Reachability distances (RD) ve... | g63222 | [
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<p>I have read that the update equation for stochastic gradient descent is as shown below, for each iteration, k. Does one iteration correspond to one training example? So for each example is there only one update to $\theta$? </p>
<p>$ \theta^{k+1} = \theta^k - \epsilon_k \frac{\partial L(\theta^k,z)}{\partial \th... | g63223 | [
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<p>I am using Netflix data as my dataset (although he competition is closed, I can still find the whole data set) But I could not find the result data. Does anyone have that testing result data ? Thanks</p> | g63224 | [
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<p>I'm currently studying Linear Regression and am wondering if somebody would help me out with a high-level comparison of different methods.</p>
<p>Just to list some: Lasso, Ridge, Elastic Net, Principal Component Regression, Least Angle Regression, Kernel Ridge Regression, Partial Least Squares, etc.</p>
<p>I'd lik... | g20799 | [
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<p>I'm trying to do model selection using PyMC (v2.2), but having difficulty assessing the models using various Information Criteria and/or Bayes Factor. My model is similar to a typical regression, with several parameters (~10) with priors modelled by uniform distributions, and a single observation modelled by a norma... | g63225 | [
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<p>I have the following integral that I wish to evaluate: $\int_0^\infty x\,\, p(x)dx$. Where, $p(x)\propto \exp\left(-ax+\frac{b}{x+k}\right)$ for $a,b\ge0$</p>
<p>Firstly what would the normalising constant be, and secondly what would the expectation be. </p>
<p>In the event that a=0, this could be evaluated using ... | g669 | [
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<p>I have a variable <code>test score</code> that is measured for an organization consisting of 2050 people. The goal is to test if men outperform women (or vice versa). Unfortunately, only 50 of the 2050 people are women. I was told that in order to run inference when there is such a disproportion of one group within ... | g63226 | [
0.0027019307017326355,
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<p>Suppose that X is distributed Poisson with a known rate and Y is a normal distributed with a know mean and variance. My goal is to approximate the distribution Z where P(Z) = P(X) * P(Y), where Z is a non-negative integer. I could get a good approximation by sampling, but I'd really like to have a fast solution, i... | g63227 | [
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<p>The moment generating function that is associated with the discrete random variable $X$ and pmf $f(x)$ is defined as: </p>
<p>$$M(t) = E\left[e^{tX}\right] = \sum_{x \in S} e^{tx} f(x).$$</p>
<p>Where does this $e^{tx}$ come from? This vaguely looks like an integrating factor from differential equations. </p>
<p>... | g20802 | [
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<p>I am slowly learning Python, and I am curious if anyone has come across some easy to follow tutorials or books explaining how to program simple to intermediate statistical methods, from basic descriptive tests to regression analysis and beyond. </p>
<p>Any resource is helpful, thanks. </p> | g63228 | [
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<p>I have 6 different data sets which I need to compare. I am able to compare five of them by plotting graphs, but when I include the sixth dataset, it tanks the other datasets because while the maximum value of the other five datasets is in thousands, for the sixth dataset, the maximum values is in billions. So I get ... | g63229 | [
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0.003741... |
<p>If you can measure a time series of observations at any level of precision in time, and your goal of the study is to identify a relationship between X and Y, is there any empirical justification for choosing a specific level of aggregation over another, or should the choice be simply taken based on theory and/or pra... | g20806 | [
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0.02717704325914383,
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<p>The following problem comes from a max likelihood calculation for gaussian families, but is of independent interest.</p>
<p>Is it possible to find a closed-form approximation for small values of $x$ for</p>
<p>$\text{det}(B + xI)$</p>
<p>where I is the identity matrix and B is hermitian rank-deficient positive se... | g63230 | [
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<p>Currently i am using RF toolbox on MATLAB for a binary classification Problem</p>
<p>Data Set: 50000 samples and more than 250 features</p>
<p>So what should be the number of trees and randomly selected feature on each split to grow the trees?
can any other parameter greatly affect the results?</p> | g63231 | [
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<p>I have a smooth but rather complex curve, sampled with a good frequency. I apply the discrete Fourier transform to it using the fast Fourier transform (FFT) algorithm and get its Fourier image. I need to find peaks on the resulting Fourier transform curve, but the image I get contains a substantial amount of noise, ... | g63232 | [
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<p>I analyze a set of multivariate measurements. It is known that several pairs of independent variables show high linear correlation. The graph below shows a scatterplot of one such pair (X and Y, upper pane), as well the residuals as a function of Y (lower left pane) and the histogram of these residuals (lower right ... | g976 | [
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<p>I'm working on a multiple logistic regression in R using <code>glm</code>. The predictor variables are continuous and categorical. An extract of the summary of the model shows the following:</p>
<pre><code>Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) 2.451e+00 2.439e+00 1.00... | g63233 | [
-0.018785007297992706,
-0.011362632736563683,
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-0.03600456565618515,
-0.02474776841700077,
0.015042065642774105,
0.0591488815844059,
0.00... |
<p>If one truncates a distribution, for example like the zero truncated poisson distribution:</p>
<p><a href="https://en.wikipedia.org/wiki/Zero-truncated_Poisson_distribution" rel="nofollow">https://en.wikipedia.org/wiki/Zero-truncated_Poisson_distribution</a></p>
<p>or more general:</p>
<p><a href="https://en.wiki... | g10328 | [
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0.003535918425768614,
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-0.00... |
<p><a href="http://code.google.com/intl/pl-PL/apis/predict/">Google Prediction API</a> is a cloud service where user can submit some training data to train some mysterious classifier and later ask it to classify incoming data, for instance to implement spam filters or predict user preferences.</p>
<p>But what is behin... | g63234 | [
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<p>What analyses can be used to find an interaction effect in a 2-factor design, with one ordinal and one categorical factor, with binary-valued data?</p>
<p>Specifically, are there any types of analyses that are capable of dealing with a 2 factor design 5(ordinal) x 2(categorical), where the outcomes are either true ... | g20815 | [
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<p>Can someone please explain why clustered standard errors ensure that the error estimates of Pooled OLS results are appropriate?</p> | g63235 | [
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<p>Trace metals in drinking water affect the flavor of the water, and unusually
high concentration can pose a health hazard. The following Table shows trace-metal concentrations (zinc, in mg/L) for both surface water and bottom water at six different river locations. Our aim is to see if surface water concentration (x)... | g63236 | [
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<p>I am sampling a beta using a Gibbs sampling. It is variable selection model. So in different iteration of gibbs different covariates are included to the model (denoted by a variable selection indicator $\gamma$). However, this indicator have high variance ( this is because my covariates are correlated). I use: $\hat... | g63237 | [
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-0.011843947693705559,
0.007410932797938585,
0.008986547589302063,
-0.05403720587491989,
0.0527043379843235,
-0.052141886204481125,
0.... |
<p>i have a set of data that is generated by expensive computational model evaluations, on a total data set of 10000 samples in 40 dimensions. This sample data set is composed of different data sets, originating partly from random runs, latin hypercube DOE, radial design DOE, linear parameter studies, and a large part... | g20817 | [
-0.018107494339346886,
-0.013921861536800861,
-0.002271901583299041,
-0.06292461603879929,
-0.004644803237169981,
-0.012783781625330448,
0.030825147405266762,
0.006431332789361477,
-0.05170086771249771,
-0.0025601719971746206,
-0.008039257489144802,
0.0522812157869339,
0.043793536722660065,
... |
<p>I processed rpart( ) on the same dataset. One did not use the control parameter "minsplit", but the other one did. I do not understand why I got the different first node in two processes. My understanding is that the "minsplit" will only extend the branches of the tree, but it should not change the structure of t... | g63238 | [
0.05885778367519379,
-0.03966565057635307,
0.014974020421504974,
-0.031081557273864746,
-0.002434714464470744,
-0.04443243145942688,
0.007106006611138582,
0.03391052410006523,
-0.016423813998699188,
-0.04330497607588768,
0.01424099039286375,
0.008660590276122093,
0.022051814943552017,
0.01... |
<p>I have a set of real numbers $x_{1}...x_{n}$ and would like to estimate their mean (let's call it y) so that $median(x_{i}-y)^{2}$ is minimal. </p>
<p>Is there an algorithm and a correctness proof for finding it?</p>
<p>I understand I need to look at segments of the type $[x_{i},x_{i+n/2}]$ and check for the short... | g20818 | [
0.021933991461992264,
-0.04028816148638725,
-0.024520499631762505,
-0.0036749658174812794,
-0.01330757699906826,
-0.07408401370048523,
-0.029894497245550156,
-0.00903026107698679,
-0.03355790674686432,
-0.000046402561565628275,
-0.004379785619676113,
0.04611159488558769,
0.004215448629111051... |
<p>Looking at the Wikipedia article on <em>Conjugate prior</em>, in the section on <em>Continuous distributions</em>, We see the first two entries discuss "Normal with known variance" and "Normal with known precision". The "Interpretation of hyperparameters" column refers to the "sum of individual precisions". While I ... | g63239 | [
0.05256741866469383,
0.00036696234019473195,
-0.00844647828489542,
-0.030892258509993553,
-0.034390274435281754,
-0.004216112196445465,
0.07618273049592972,
-0.003404011484235525,
-0.03488096967339516,
-0.03386389836668968,
-0.021758107468485832,
-0.0033106969203799963,
-0.01502018328756094,... |
<p>Suppose:
$u_t \sim N(0,1) \ iid.$, $X_t = g(X_{t-1}) \cdot u_t$ whereas $g(X)$ can be any deterministic function.
Is this sufficient to define a martingale?</p>
<p>So does it hold: $E(X_t|X_{t-1}, \ldots , X_1) = E(g(X_{t-1}) \cdot u_t|X_{t-1}, \ldots , X_1) =^{\ pi.} E(g(X_{t-1})|X_{t-1}, \ldots , X_1) \cdot E(u_t... | g63240 | [
-0.02438996732234955,
0.01960528828203678,
-0.003783773398026824,
0.0008544044103473425,
0.017335981130599976,
-0.013563540764153004,
0.04343777894973755,
-0.0418173223733902,
-0.07999171316623688,
-0.00869357492774725,
-0.041325658559799194,
0.11020255088806152,
0.06765548884868622,
0.015... |
<p>I'd really appreciate a point in the right direction of what models I should study, and the best modelling approach to evaluate a sentencing policy.</p>
<p>I certainly am not asking for a full solution, but it would save me a huge amount of time if I knew where to start. I have experience of time series models with... | g63241 | [
0.026469016447663307,
0.044893376529216766,
-0.0150975426658988,
-0.03737398236989975,
-0.01100944820791483,
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0.05234171822667122,
0.01732085831463337,
-0.08507051318883896,
0.027528958395123482,
0.028575310483574867,
0.00834657158702612,
0.0540575310587883,
0.02226123... |
<p>I read a paper which used normalized correlation to evaluate the distance between two vectors. But I searched on the Internet and found little about normalized correlations, but I still got some clues. In one paper the formula for normalized correlation is given as follows:</p>
<p>$$dc(y_1,y_2) = \frac{y_1^T y_2}{|... | g28593 | [
0.08496908843517303,
-0.07441785931587219,
-0.009862704202532768,
-0.02660081535577774,
-0.01887616142630577,
0.044463299214839935,
0.05307783931493759,
0.029101649299263954,
-0.013210441917181015,
-0.04236491024494171,
0.013971852138638496,
0.046182382851839066,
0.030851926654577255,
-0.0... |
<p>If $Z$ is $\mathcal N(0, 1)$, and $Z^2$ is $\chi^2_1$, is $\frac Z {\sqrt{Z^2/n}}$ a $t$ distribution with $n=1$ degree of freedom?</p> | g63242 | [
-0.010247753001749516,
-0.009647631086409092,
-0.021239453926682472,
0.025133170187473297,
0.023277930915355682,
-0.040876131504774094,
0.02675860933959484,
-0.023100513964891434,
0.05300970375537872,
0.018318770453333855,
-0.029517989605665207,
0.017637377604842186,
-0.02459506317973137,
... |
<p>I am conducting a study on neurological diseased patients. I am looking into possible factors related to time-to-dementia. Costs associated with neurological testing allow us to assess all patients in the prospective cohort on an annual basis. We have (can afford) 4 fixed follow up visits for all patients - baseline... | g63243 | [
-0.018360385671257973,
0.004790322855114937,
0.004878893494606018,
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0.04727407172322273,
0.022897932678461075,
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0.05154332518577576,
0.060261938720941544,
0.04946428909897804,
0.057516805827617645,
-0.... |
<p>Here is the situation:</p>
<p>I want to sell my house.
The price I'm getting from people who want to by my house follows i.i.d. with $X_n \sim \text{Uniform}(0,1)$, where $X_n$ is the highest offer on the $n$th day.
I spend $C<0.1$ for advertising my house.
My overall profit is $X_n-C_n$ when I sell the house on... | g63244 | [
-0.01578766666352749,
-0.007373626809567213,
-0.03631361573934555,
-0.016462208703160286,
0.03802098333835602,
-0.05881185084581375,
0.02085859142243862,
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-0.019220922142267227,
-0.01575746014714241,
0.02563694305717945,
-0.0008923363056965172,
... |
<p>I have Two samples that I want to test (using python) if they are drawn from the same distribution. To do that I use the statistical function ks_2samp from scipy.stats. It returns 2 values and I find difficulties how to interpret them.
Help please!</p> | g48555 | [
0.003254892537370324,
-0.01943635195493698,
-0.00032374102738685906,
-0.0555342473089695,
0.0071128131821751595,
0.01332085020840168,
-0.04818040877580643,
0.009154080413281918,
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-0.017008928582072258,
-0.011820066720247269,
0.010248878970742226,
0.037251755595207214,
... |
<p>I have a data like this: </p>
<pre><code>ds <- structure(list(return = c(-1.11777941176471, -0.883516129032258,
3.71416129032258, 0.028483870967742, -2.05184375, -0.26984375,
5.07122058823529, 15.54915625, 0.557730769230769, 3.40277358490566
), factor_5 = c(0L, 1L, 1L, 0L, 0L, 1L, 1L, 1L, 0L... | g20824 | [
0.005866821855306625,
-0.022022724151611328,
-0.013251683674752712,
-0.04084030166268349,
0.02787688374519348,
-0.030793294310569763,
0.041424330323934555,
-0.04319785162806511,
-0.030836939811706543,
-0.05673309415578842,
0.08018922060728073,
0.044830869883298874,
0.05237523093819618,
-0.... |
<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/38118/parallel-lines-on-residual-vs-fitted-plot">Parallel lines on residual vs fitted plot</a> </p>
</blockquote>
<p>I'm regressing the time it took for an event to happen on another, normally-distributed ... | g49670 | [
0.08843233436346054,
-0.02268316224217415,
-0.035337526351213455,
-0.027579866349697113,
-0.012867110781371593,
-0.012647743336856365,
-0.0011961436830461025,
0.02181978151202202,
-0.04243773967027664,
-0.03638115152716637,
0.02747993916273117,
0.03507614880800247,
0.0319460891187191,
-0.0... |
<blockquote>
<p>A team has conducted a study in which an introductory class was
randomly divided into two groups. Group 1 was administered a dosage of
alcohol. Group 2 was given an equvialent dosage of marijuana. Fifteen
minutes after administration, both groups were asked to solve a
puzzle. The experimenter ... | g63245 | [
0.016209421679377556,
0.0126862283796072,
0.0048330784775316715,
-0.028825944289565086,
0.022477488964796066,
-0.06705763190984726,
0.003025633981451392,
-0.020599912852048874,
-0.03474864363670349,
0.01652832143008709,
0.06304258853197098,
0.003666926408186555,
0.01758161559700966,
-0.001... |
<p>I have a dataset of 500 observations (firms) and for each firm I know how they are directly and indirectly related based on some characteristics. I can therefore construct a network of connectivity across all stocks. For each firm I compute the shortest path to all other firms. I end up with 500 networks of degree o... | g63246 | [
0.01813695952296257,
0.0005067414022050798,
0.004325471352785826,
-0.0252866018563509,
0.022081634029746056,
-0.04283766821026802,
0.044611893594264984,
0.011861762963235378,
-0.008151811547577381,
-0.03827334940433502,
-0.019118815660476685,
-0.0090941758826375,
0.058955661952495575,
-0.0... |
<p>I am using 2007's Social Security Life Table: <a href="http://www.ssa.gov/oact/STATS/table4c6.html" rel="nofollow">http://www.ssa.gov/oact/STATS/table4c6.html</a></p>
<p>I would like to use the table to generate a number for each scenario I ran. This number represents the remaining life (in years) scenario n will l... | g20826 | [
0.03067675232887268,
-0.015010672621428967,
0.014991008676588535,
-0.04725360870361328,
-0.04381183534860611,
-0.028273705393075943,
0.04137938842177391,
-0.028130561113357544,
-0.017131511121988297,
0.001090186065994203,
0.011676046997308731,
-0.001442566281184554,
0.05180605128407478,
0.... |
<p>Has anyone gone through some papers using Vector Error Correction Models in causality applications with more than one cointegration vectors, say two. I guess there will be more than one ECM terms. How to assess the endogeneity of the left hand variables if t-stats on different ECM coefficients yield different (conf... | g63247 | [
0.07757062464952469,
-0.08965905010700226,
-0.004986800719052553,
-0.015215094201266766,
0.06595081835985184,
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0.07862484455108643,
0.050765614956617355,
-0.06438819319009781,
0.05812552198767662,
-0.019853610545396805,
0.01486516185104847,
0.033384039998054504,
0.009... |
<p>Given a list of p-values generated from independent tests, sorted in ascending order, one can use the <a href="http://www.math.tau.ac.il/~ybenja/MyPapers/benjamini_hochberg1995.pdf">Benjamini-Hochberg procedure</a> for <a href="http://en.wikipedia.org/wiki/False_discovery_rate#Independent_tests">multiple testing cor... | g63248 | [
0.05234532430768013,
-0.06010610982775688,
-0.01949925720691681,
-0.0009624618105590343,
0.013174778781831264,
-0.028951281681656837,
0.004540702793747187,
0.03720865398645401,
-0.06049647554755211,
0.003039405681192875,
0.0018978527514263988,
-0.0166852418333292,
0.04518510028719902,
0.05... |
<p>I realize this is pedantic and trite, but as a researcher in a field outside of statistics, with limited formal education in statistics, I always wonder if I'm writing "p-value" correctly. Specifically:</p>
<ol>
<li>Is the "p" supposed to be capitalized?</li>
<li>Is the "p" supposed to be italicized? (Or in mathema... | g63249 | [
0.02444634959101677,
0.014640484005212784,
0.021334564313292503,
-0.04955596104264259,
0.02110287919640541,
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0.018284481018781662,
-0.03932265564799309,
-0.01707322709262371,
0.021326085552573204,
-0.004336500074714422,
0.06290058046579361,
-0.0... |
<p>I am trying to detect text in a scanned document by examining variations in the lightness of the scan collapsed vertically. Here's a sample of the input I would receive, with the lightness plot of each vertical pixel strip superimposed:</p>
<p><img src="http://i.stack.imgur.com/coUW6.jpg" alt="Example"></p>
<p>Not... | g20832 | [
0.019708989188075066,
-0.013906148262321949,
-0.024098671972751617,
-0.03124958835542202,
-0.0005509242182597518,
-0.02420208416879177,
0.02914801985025406,
0.03876141086220741,
-0.0359407439827919,
-0.013828451745212078,
-0.037971049547195435,
0.02410239167511463,
0.05182460695505142,
0.0... |
<p>Genetic algorithms are avoided in econometry literature as often as possible, but still sometimes they are inevitable. The question is: <strong>Which well known models are the most difficult to estimate using conventional algorithms?</strong> (By Conventional algorithms I mean Gauss-Newton method, Levenberg–Marquard... | g63250 | [
0.04674354940652847,
0.04481283575296402,
-0.0010599488159641623,
0.017168914899230003,
0.004989232402294874,
-0.0034183626994490623,
0.008619418367743492,
0.007293612230569124,
-0.01946950890123844,
0.10040559619665146,
0.007472158409655094,
-0.01123389508575201,
0.03454374521970749,
0.01... |
<p>I have a project in which I need to perform orthogonal regression in a multivariate space. For the univariate case, I've found Teetor's R Cookbook suggests using principle components:</p>
<pre><code>reg_orth = prcomp( ~ y + x, data=ds[train,])
reg_orth_slope = reg_orth$rotation[2,1]/reg_orth$rotation[1,1]
reg_orth... | g20837 | [
-0.014416679739952087,
-0.031598180532455444,
-0.032354678958654404,
-0.04989847168326378,
-0.05686312913894653,
-0.06603068858385086,
0.059687837958335876,
0.018595146015286446,
0.001141229411587119,
-0.04597469046711922,
-0.0010167573345825076,
-0.006446636747568846,
0.015749434009194374,
... |
<p>It confuses/blows my mind that the Binomial has variance proportional to $p(1-p)$. Equivalently, the Fisher information is proportional to $\frac{1}{p(1-p)}$. What is the reason for this? Why is the Fisher Information minimized at $p=0.5$? That is, why is inference most difficult at $p=0.5$?</p>
<h3>Context:</h3>
... | g18468 | [
0.04742996767163277,
0.03508136793971062,
-0.017572611570358276,
-0.011723940260708332,
0.033797502517700195,
-0.04264732450246811,
0.030170932412147522,
0.0026041718665510416,
-0.06330464780330658,
-0.028847694396972656,
-0.028681274503469467,
0.005489557981491089,
-0.01631874032318592,
0... |
<p>I am a little confused by Ito's lemma. I reviewed the basic application for geometric brownian motion. I'm now trying to apply it to a different functional form to make myself better. My mind leaps to the following:</p>
<p>\begin{equation}
dx=x (\mu dt+(\sigma+\delta^t) dz)
\end{equation}
\begin{equation*}
\delta&... | g20839 | [
-0.024007542058825493,
0.00001324810364167206,
0.001683370559476316,
-0.011058409698307514,
0.04156624153256416,
-0.05227429047226906,
0.09456686675548553,
-0.048336949199438095,
-0.05154023319482803,
-0.025934236124157906,
-0.04228942468762398,
0.05051208287477493,
0.09519586712121964,
-0... |
<p>If we have a linear gaussian model where we have, </p>
<p>$P(Z) = \mathcal{N}(\mu_z,\sigma^2_z)$ and</p>
<p>$P(X|Z) = \mathcal{N}(w_o+zw,\sigma^2_x)$</p>
<p>How do we calculate the marginal </p>
<p>$P(X) = \int_Z P(Z)P(X|Z)$ ?</p> | g20841 | [
-0.009060940705239773,
-0.0588252954185009,
-0.02320133149623871,
-0.012768395245075226,
0.007351644802838564,
0.008353441953659058,
0.026545418426394463,
-0.0032757287845015526,
-0.015021431259810925,
0.025665780529379845,
-0.023054061457514763,
0.055244479328393936,
0.040665365755558014,
... |
<p>Let's say I have a (ads live days, revenue) data set. <br>
The data set shows how much revenues each ads generates during the days it is live. <br></p>
<ul>
<li>ads1 generates 100 dollars during the 5 days when it is live. </li>
<li>ads2 generates 200 dollars during the 10 days when it is live. </li>
<li>ads3 gene... | g63251 | [
0.009759072214365005,
0.010854996740818024,
-0.04547600820660591,
-0.032171063125133514,
0.012768009677529335,
-0.013047726824879646,
0.039266303181648254,
-0.02541252225637436,
-0.021241534501314163,
-0.046969108283519745,
0.05041693150997162,
0.07508581876754761,
0.04695575311779976,
-0.... |
<p>In Frank Schorfheide's class notes on <a href="http://www.webpages.ttu.edu/pesummer/ECO%205328/notes/4%20likelihood%20dsge.pdf" rel="nofollow">likelihood functions of DSGE models</a>, he expresses the value of the likelihood function for a given vector of parameters $\theta$, and time series $Y^T$ as:</p>
<p>$$p(Y^... | g40120 | [
-0.046702753752470016,
-0.012505986727774143,
-0.02375113219022751,
0.004937044344842434,
0.025775378569960594,
-0.03159239888191223,
0.0887208804488182,
0.023520203307271004,
-0.0628204271197319,
0.01880769617855549,
-0.03680793568491936,
0.04765830188989639,
0.0573459267616272,
0.0359823... |
<p>I tried to simulate from a bivariate density $p(x,y)$ using Metropolis algorithms in R and had no luck. The density can be expressed as $p(y|x)p(x)$, where $p(x)$ is Singh-Maddala distribution </p>
<p>$p(x)=\dfrac{aq x^{a-1}}{b^a (1 + (\frac{x}{b})^a)^{1+q}}$
</p>
<p>with parameters $a$, $q$, $b$, and $p(y|x)$ is... | g20844 | [
0.01960853300988674,
-0.04512462764978409,
0.004989637527614832,
-0.04593811556696892,
-0.05640334263443947,
-0.006207963451743126,
-0.023006688803434372,
-0.05000848323106766,
-0.03282325714826584,
0.01688610576093197,
0.04269053041934967,
0.017687330022454262,
0.07599812000989914,
0.0218... |
<p>This is the confidence interval estimated by prop.test</p>
<pre><code>n <- 600; x <- 276; p <- 0.40
prop.test(x, n, p, alternative="two.sided", conf.level=0.95, correct=T)
95 percent confidence interval:
0.4196787 0.5008409
</code></pre>
<p>I tried to reproduce it, reading the code under prop.test. Here... | g63252 | [
0.02213439531624317,
-0.028524991124868393,
0.0010640952968969941,
0.049019649624824524,
0.011838004924356937,
0.03731086105108261,
0.04577111825346947,
0.009885330684483051,
-0.05348614975810051,
-0.018387047573924065,
0.0005966738681308925,
0.06481324136257172,
0.0045869797468185425,
-0.... |
<p>I have a survey data set with missing values and I generated 10 multiple imputations in which the missing values were imputed. There are several categorical variables in the data sets and I'd like to see if there's any association among these variables using chi-squared test.</p>
<p>However, I've been searching how... | g63253 | [
0.027993252500891685,
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0.009768589399755001,
0.00009983789641410112,
0.02216312102973461,
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0.00947040505707264,
0.005939877592027187,
-0.005271433386951685,
-0.02686610445380211,
0.0025522031355649233,
0... |
<p>As the title says, I need to perform a Pooled OLS, a Fixed effects and a Random effects analysis. In the case of a normal OLS, one should test for normality, collinearity, homoscedasticity, linearity, etc.</p>
<p>I have been following the steps described <a href="http://www.ats.ucla.edu/stat/stata/webbooks/reg/cha... | g63254 | [
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0.03042060323059559,
0.018374906852841377,
0.0... |
<p>I will be working with a dataset sample which I will use for optimization purposes. However, before I start, I want to briefly analyze data in order to get a better sense and identify possible directions to explore. </p>
<p>My problem is I don't know how the data was sampled, which sampling method was used or wheth... | g20847 | [
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0.... |
<p>I have a heat-map of gene expression measurements (log<sub>2</sub>-transformed microarray signals, after inter-microarray data normalization, etc.) that I am using to illustrate the expression of 72 genes ('rows' of the heat-map) which I had identified as differentially expressed among different sub-groups of the 60... | g63255 | [
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-0.027404826134443283,
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0.08247256278991699,
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0.008... |
<p>This question came up in a consulting context, and I was interested in your thoughts.</p>
<h3>Context</h3>
<p>One strategy for dealing with occasional missing data when calculating scale means looks like this in the language of SPSS:</p>
<pre><code>COMPUTE depmean = mean.4(dep1, dep2, dep3, dep4, dep5, dep6).
EX... | g63256 | [
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0.03638501465320587,
-0.01924586109817028,
-0.0019547969568520784,
-0.015188698656857014,
-0.03972809761762619,
0.018749618902802467,
-0.06260441988706589,
0.048138558864593506,
... |
<p>I am working on 4 different species of tomatoes. From the data I had, I looked at the occurrence of a particular "event" in certain intervals of their genome (this interval is identical in all 4 plants) and I have a file for each of the species with their probability of occurrence. The file looks something like this... | g63257 | [
0.021780796349048615,
0.014221607707440853,
-0.027239156886935234,
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0.024487288668751717,
0.051812101155519485,
-0.07497983425855637,
-0.023259993642568588,
-0.018852539360523224,
-0.001243776292540133,
0.02212424762547016,
... |
<p>I have a data frame that contains some duplicate ids. I want to remove records with duplicate ids, keeping only the row with the maximum value.</p>
<p>So for structured like this (other variables not shown):</p>
<pre><code>id var_1
1 2
1 4
2 1
2 3
3 5
4 2
</code></pre>
<p>I want to generate this:</p>
<pre><code... | g20853 | [
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0.03437930345535278,
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-0.02665148675441742,
0.05159720405936241,
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0.07368099689483643,
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-0.0198559258133173,
-0.030023112893104553,
0.01281909178942442,
0.007204149384051561,
0.031... |
<p>I have N objects which can have either 1 or both properties, A & B. I want to know if having property A raises the chance of having property B. </p>
<p>My data is:</p>
<p><img src="http://i.imgur.com/4ILrUtG.png" alt="data"></p>
<p>Where S means they have the property, and N means they dont (ie, 263 objects h... | g63258 | [
0.04574277251958847,
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0.04668808728456497,
0.04623031243681908,
0.0311385877430439,
-0.02504... |
<p>Let's say I've collected a <em>small</em> number (N) of observations about a hypothesis that I'd like to test. I could use the bootstrap method to produce a sample distribution for the mean result of N observations, but I'm concerned that this model could break down when N gets very small, introducing error into the... | g10356 | [
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0.0008245431818068027,
0.05841132253408432,
... |
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