question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Suppose I have two variables (e.g., Blood Pressure and Cholesterol) and I want to investigate their association across time. Also suppose that each individual has been measured three times (longitudinally) on each variable. So, the data might look something like this:</p>
<pre><code> ID Time BP CH
1 1 1 124 ... | g63148 | [
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<p>Look at the following plot and ignore the solid lines please (just look at the dotted/dashed ones). </p>
<p><img src="http://i.stack.imgur.com/0QaAa.jpg" alt="enter image description here"></p>
<p>ONE curve is described by the following parameters and ONE fixed value for the second input parameter V:</p>
<ul>
<li... | g63149 | [
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<p>I want to compute, using the Survey of Consumer Finances (SCF) database, how much the one percent wealthier concentrates. The variable I'm using to measure wealth is the "networth". The problem is that this variable has negative values and, as far as I know, we cannot do this calculation with negative values. The re... | g98 | [
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<p>If $X\sim\chi^2_{6}$, what is the probability density function of $T = \frac{(X-6)}{\sqrt12}$?</p>
<p>The problem I'm confronted with is that the chi-squared random variable, $X$, can assume only positive values while the random variable $T$ can assume both positive and negative values.</p>
<p>I tried to use both ... | g63150 | [
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<p>Suppose we have a moving object (a horizontal projectile motion as one of the most basic examples). Is there any way to predict where it will hit finally? Please note that I'm looking for a machine learning method not a closed form solution.</p>
<p>Although we can track the motion, using Kalman filter, that is only... | g63151 | [
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<p>I am doing final revisions to my dissertation, which includes a large number of regressions. I have six outcome variables (DVs) and I am testing the effect of four primary (correlated) IVs, but I am testing them separately to determine the unique contribution to the model of each IV. Therefore, I have 24 regression... | g20670 | [
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<p>I have a specific regression problem of which I am not sure how to solve it.
We have a dependent variable which varies depending on a certain area that is electrically stimulated in the brain. The stimulation location is represented as 3D coordinates. A multiple regression with the three coordinates (i.e. axes) as ... | g63152 | [
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<p>I have a variable z which has around 3000 values between 0.0 and 0.5.</p>
<p>I have plotted here z in the y-axis and 3000 evenly spaced numbers over the interval 0.0 and 0.5 in the x-axis so that one can see my data distribution.</p>
<p><img src="http://i.stack.imgur.com/d9DMf.png" alt="enter image description her... | g63153 | [
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<p>I have a dataset of 300 text documents that I have manually classified into three classes. The first two classes are relatively equal in size; the third class is about 40% larger than each of the individual first two classes. </p>
<p>The classes are very similar, i.e. they share similar features. After pre-proce... | g63154 | [
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<p>I am using gbm package for classification. As expected, the results is good. But I am trying to understand the output of the classifier.
There are five terms in output. </p>
<pre><code>`Iter TrainDeviance ValidDeviance StepSize Improve`
</code></pre>
<p>Could anyone explain the meaning of each term, especi... | g28562 | [
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<p>I want to use/adapt a recommendation algorithm for posters in an e-commerce. The thing is that I want to use previous categories searched before posting in a particular category (has to be at a very granular level), so I need to create rules that always comes up with the posting/replying class. So I have 2 different... | g63155 | [
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<p>The Pareto principle is used surprisingly widely in business. I'm wondering how correct it's wide use is. It seems as though it is often used without empirical verification as if the situation fits a Pareto distribution a priori.</p>
<p>Here's an example:</p>
<p>Let's say there is a retail store with a wide range ... | g63156 | [
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<p>Is it known what is the LIBSVM time complexity when using RBF kernel functions?</p> | g20677 | [
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<p>This is used in information retrieval.
I have an algorithm that uses a sample set to predict a yes / no.
I think the correct term is binomial.
Yes this document is about sports or no this document is not about sports. </p>
<p>I need to represent the effectiveness of the algorithm with that population and that ... | g63157 | [
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<p>I am looking for some linearly inseparable classification problems and nonlinear regression problems. What are some public data sets?</p> | g20679 | [
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<p>I have a Poisson GLM in R that is over dispersed, so I fit a quasipoisson GLM, however the residual deviance nor the degree of freedom change.
Can that happen? What does it mean in that case?</p>
<p>Thank you.</p> | g63158 | [
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<p>I have survey data about injuries occurring to athletes over the span of their careers. Many of the athletes suffered multiple injuries (the most any athlete reported was five and this did not occur very often). While I can see that injuries within an athlete may be dependent on a previous injury, in the data, many ... | g43429 | [
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<p>I received a comment about my article from one of the reviewer but I do not understand what I should do. Here is a short explanation of the study:
This study investigated the influence of lectures about the Renaissance and abstract art on ratings of paintings from these two periods in art history. The study included... | g20682 | [
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<p>I have this shifted time series data. For one set consists of features from week1-5 and labels at week6. Another set features from week2-6 and labels and week7 and so on. I have like four sets of them. If I consider the individual set, then the positive labels are very scarce. So I was thinking of concatenating thes... | g63159 | [
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<p>I have some data points and I fitted a function (2nd order polynomial here) to the data. The algorithm (<code>scipy.optimize.curve_fit</code>) gave me the optimal parameters and the covariance matrix of those parameters. In the documentation, it says that the square roots of the diagonal entries give the errors for ... | g20690 | [
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<p>This is for a simple psychology report.</p>
<p>I was wondering if I could hypothesise an insignificant mediation.</p>
<p>Eg: "...based on this research it is predicted that group identity is not a significant mediator (or does not sognificantly control) narcissism's relationship with aggression."</p>
<p>Then I wo... | g63160 | [
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<p>I read that in a regression with $k$ regressors, the t-statistic corresponding to a certain coefficient follows a $t(n-k)$ distribution. However, later on I read that studentized residuals follow a $t(n-k-1)$ distribution. How could it be that the extra degree of freedom is lost: isn't this also just based on a regu... | g63161 | [
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<p>first of all - I am not really into regression analysis (I have performed some linear regressions) and my statistic/econometric skills are more or less elementary.</p>
<p>I have panel data (several countries over a certain time period) and I would like to apply a formula such as this:</p>
<p><img src="http://i.sta... | g20692 | [
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<p>Assume we are given a $p \times n$ (variables $\times$ data points) data matrix $X$, with $p > n$ (i.e. more variables than data points). Performing PCA on such a matrix yields an $n \times n$ eigenvector matrix $U$ (instead of the desired $p \times p$, because $p > n$).</p>
<p>Now suppose we use the eigenval... | g20693 | [
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<p>Suppose $P(X=1)=P(X=-1)=1/2$ and define </p>
<p>$$X_n=\begin{cases} X\ \text{with probability}\ 1-\frac{1}{n} \\ e^n\ \text{with probability}\ \frac{1}{n} \end{cases}$$</p>
<p>I then need to prove or disprove that $X_n$ converges to $X$ in probability, distribution and quadratic mean.</p>
<p>For the convergence i... | g49664 | [
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<p>I would appreciate any help! Specifically I would like to know which option is best.</p>
<p><em>Question</em> Does Var2 influence Var1 in relation to the factor(Ind), and does Var3 & Var4 also have some effect. </p>
<p><strong>The problem</strong>
I have multiple observations of Var1 per factor level (or per ... | g63162 | [
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<p>In Monte Carlo simulation, we often consider how well a sequence of generated points are. If I am correct, one aspect is <a href="http://en.wikipedia.org/wiki/Statistical_randomness" rel="nofollow">statistical randomness</a>:</p>
<blockquote>
<p>A numeric sequence is said to be statistically random when it contai... | g63163 | [
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<p>I have a random variable, X, with cdf $F$ and pdf $f$. I want to estimate a parameter of $F$, say mean, $\mu$.</p>
<p>So what do I do? I construct an <em>estimator</em>, $Y_n$, with several random variable X1, X2,..., Xn from $F$ such that,</p>
<p>$Y_n=g(X1, X2, ..., Xn)$</p>
<p>and make sure that the random vari... | g63164 | [
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<p>I'm <a href="http://www.quuxlabs.com/blog/2010/09/matrix-factorization-a-simple-tutorial-and-implementation-in-python/" rel="nofollow">reading about matrix factorization for recommender systems</a>. A basic matrix factorization model would be something like: $(p_i \times q_j ) + b_i + b_j$. That formula would comput... | g63165 | [
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<p>I am trying to fit coxph a model with frailty with syntax below:</p>
<pre><code>> kidneyExt.cox <- coxph(Surv(time,inf) ~ age+sex+frailty(patient)+strata(type), data=kidneyExt)
> kidneyExt.cox
Call:
coxph(formula = Surv(time, inf) ~ age + sex + frailty(patient) +
strata(type), data = kidneyExt)
... | g63166 | [
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<p>I am learning RBM (restricted Boltzmann machine) for deep learning.
The log-likelihood of RBM is given as : </p>
<p><img src="http://i.stack.imgur.com/1AOEC.png" alt="enter image description here">
and its gradient w.r.t. the parameter is: </p>
<p><img src="http://i.stack.imgur.com/5smlF.png" alt="enter image des... | g63167 | [
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0.06012805923819542,
0.009... |
<p>I do not have hypotheses for my research and I have got only categorical data. what kind of data analysis can i conduct for correlation between variables? also is chi-square used only for hypotheses testing? can it be used for exploratory analysis? and how to test if there is moderation relationship between variabl... | g20695 | [
0.029152894392609596,
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0.010589770041406155,
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0.01427637692540884,
0.0028135834727436304,
0.029832717031240463,
0.0... |
<p>I'm thinking of implementing my own boosting algorithm, so I'm looking for any multiclass classfication algorithms that would support weighting of the examples, i.e. you could specify what examples are more important to affect algorithm optimisation. </p>
<p>Of course I know about decision trees, but I'm looking fo... | g20696 | [
0.031070107594132423,
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0.014866904355585575,
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0.037810318171978,
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0.029048165306448936,
0.07617256790399551,
0.10... |
<p>I have the output of a couple of Socprog models and I'd like to see if the results are statistically significant.</p>
<p>Group A output: <code>mean=55.8 SD=25.6 (95% C.I. 38.5–113.4), n=66</code><br/>
Group B output: <code>mean=28.9 SD=11.8 (95% C.I. 6.0–36.2), n=116</code></p>
<p>I thought perhaps generating the ... | g63168 | [
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0.03502603620290756,
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0.02602504938840866,
0.00041233631782233715,
0.027995193377137184,
... |
<p>I am attempting to predict levels of body dissatisfaction from a number of independent variables.</p>
<p>The dependant variable is Body dissatisfaction = overall score on a body dissatisfaction scale.</p>
<p>The independent variables (predictors): </p>
<ol>
<li><p>Self esteem levels = overall score on Rosenberg S... | g20697 | [
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0.06263288855552673,
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... |
<p>I am a total newbie when it comes to time series, so it is quite possible this question is duplicated somewhere else, only that I cannot find it because I don't know what this feature is called.</p>
<h3>My data:</h3>
<p>I have weekly measurements of a variable "change in rank". I also have weekly measurements of a... | g22606 | [
0.01447357703000307,
0.008418390527367592,
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0.0037805764004588127,
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0.003756438847631216,
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0.04464678838849068,
0.03427531570196152,
0.03699... |
<p>I would like to compute the measure of similarity between two ordered sets of points---the ones under <strong>User</strong> compared with the ones under <strong>Teacher</strong>: </p>
<p><img src="http://i50.tinypic.com/2uj0580.jpg" alt="Example"></p>
<p>The points are curves in 3D space, but I was thinking that t... | g63169 | [
0.0038237478584051132,
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0.01219630241394043,
0.008030670695006847,
0.04026169329881668,
0.03718065470457077,
-0... |
<p>Given a data, I'd like to utilize it by two different models, such as generalized linear model (GLM) and generalized partial linear model (GPLM), and my problem is how to compare the performance of these models?
Please give me some ideas! Thanks!</p> | g63170 | [
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0.01393479947000742,
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0.024237317964434624,
0.05701171234250069,
0.0008585068280808628,
0.02853982336819172,
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<p>I am outputting regression in a dataset but it doesn't contain the number of observations. How can I add this to be added to the dataset?
Cheers</p> | g63171 | [
0.00474334554746747,
0.01907983422279358,
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0.008235854096710682,
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0.00031782378209754825,
0.04325615242123604,
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0.011762531474232674,
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0.02966359630227089,
0.01... |
<p>I am using the package <a href="http://cran.r-project.org/web/packages/strucchange/index.html" rel="nofollow">strucchange</a> to analyze a monthly time series. I read it in as a <code>zoo</code> object. The series looks something like this:</p>
<pre><code> date A B
2 1979-01-07 ... | g20699 | [
0.007238855119794607,
-0.02233709953725338,
-0.011504653841257095,
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0.00674935569986701,
-0.051924899220466614,
0.05383356660604477,
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-0.06091965734958649,
-0.044923052191734314,
0.0019198199734091759,
0.015462762676179409,
0.002091384958475828,
0... |
<p>I want to use generalized partial linear model to fit a data. So are there
some existing functions about GPLM? I'm new about R.</p> | g20701 | [
0.01621467061340809,
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0.004175254143774509,
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0.001642231596633792,
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0.021863384172320366,
-0.... |
<p>I'm currently working on a series of Poisson time series models trying to estimate the effect of a change in how the counts were obtained (switching from one diagnostic test to another) while controlling for other trends over time (say a general increase in the incidence of disease). I've got data for a number of di... | g63172 | [
0.03561941161751747,
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-0.03337966650724411,
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0.047770943492650986,
0... |
<p>Consider the the following structural model:</p>
<p>$y=\beta_1x_1+\beta_2x_2+u$</p>
<p>where $u$ is an iid disturbance term.</p>
<p>Suppose $E(u|x_1)=0$ but $E(u|x_2)\neq 0$.For $z_2$ to be a valid instrument, it must satisfy the following two conditions:</p>
<p>1) $E(u|z_2)=0$</p>
<p>2) $E(x_2|x_1, z_2) \neq E... | g63173 | [
0.005653040949255228,
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0.049831025302410126,
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... |
<p>I meet a problem when I wanted to convert raw data into a feature vector in the data collection stage in a data mining project. Let me describe the problem first:</p>
<p>Basically, it is a time estimation problem of executing a cluster of blocks. </p>
<p>1.Block has countable number of types such as typeA, typeB, ... | g20703 | [
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0.0031722132116556168,
0.040833357721567154,
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-0.03315320611000061,
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0.03280583769083023,
0.046386152505874634,
0.022... |
<p>I am trying to find the best way to represent genetic distances in a plane so that they may use them as response variables in canonical redundancy analysis (using <code>rda()</code> in <code>vegan</code>). While there are admittedly many genetic distances to choose from, none of them are Euclidean, which produces ne... | g63174 | [
0.020467840135097504,
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0.04880744218826294,
0.034943219274282455,
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0.035103168338537216,
0.03423449024558067,
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0.03756534680724144,
0.... |
<p>In the <a href="http://pslcdatashop.web.cmu.edu/KDDCup/" rel="nofollow">2010 KDD cup</a>, participants were tasked with estimating the probability that a student would solve a particular exam question. The competition winner was whoever produced the lowest root square mean error (RMSE). Is there some theorem that gu... | g10308 | [
0.014728237874805927,
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0.0171476099640131,
0.04483671486377716,
0.0017629920039325953,
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0.04822637513279915,
0.03781898692250252,
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-0.025321122258901596,
0.033299628645181656,
0.01835792325437069,
0.06587843596935272,
-0.0038... |
<p>Imagine we have <em>C</em> cars and <em>D</em> drivers, and each driver takes a large subset of these <em>C</em> cars in order to test the rate of fuel consumption for some fixed amount of fuel (let's assume that the number of cars not tested by any given reviewer is relatively small, e.g. <20%).</p>
<p>Every dr... | g63175 | [
-0.0032935726922005415,
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0.012740778736770153,
0.03849094361066818,
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0.012663213536143303,
0.05570218712091446,
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0.029822397977113724,
0.... |
<p>I was wondering if it is possible use HoG features to train a Neural Network, I know that in the original paper by Dalal and Triggs they used the data generated to train a SVM. </p>
<p>If not is possible or <em>suitable</em> do you know a descriptor to get features in order to train a neural network.</p> | g63176 | [
0.007715938612818718,
0.019026773050427437,
0.02782472036778927,
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0.006721184588968754,
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0.11399969458580017,
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0.04049409180879593,
0.08248995989561081,
0.03... |
<p>I'm trying to analyze if the volume and sentiment (valence) of tweets has an effect on the sales of a product (in my case movies). The DV is sales with IV NumberOfTweets, Valence, DaysSinceRelease.</p>
<p>My regression analysis showed that NumberOfTweets is highly significant for Sales (p = .000) while Valence wasn... | g48382 | [
-0.03719025105237961,
0.0015160100301727653,
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0.010539459995925426,
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0.027593785896897316,
0.02651657722890377,
0.034430064260959625,
-0.005274035967886448,
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-0.002828669035807252,
0.06160910800099373,
... |
<p>I am studying a univariate and discrete time series. I know that residuals should be effectively random and have a good fit, and should have a bell shape.</p>
<p><strong>Does the plot below suggest that the residuals are effectively random?</strong></p>
<p><img src="http://hostr.co/file/970/jUNt1ui2JySM/Residui.jp... | g47900 | [
0.0013079900527372956,
0.0013143718242645264,
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0.023104352876544,
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-0.012062196619808674,
0.020570043474435806,
0.025133764371275902,
0.01092263963073492,... |
<p>I would appreciate if you could please take a look at the following attempt. I am preparing for an upcoming exam, and this is taken from a past exam paper. I would like to know if it is correct. Thank you for your time.</p>
<p>Consider the average $Y$ of $n$ independent random variables, each uniformly distributed ... | g63177 | [
0.0016676969826221466,
-0.02236224338412285,
-0.023886529728770256,
-0.03292635828256607,
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0.05542750284075737,
-0.00005707217860617675,
-0.006653112359344959,
0.00376285333186388,
-0.017460109665989876,
0.02808632142841816,
-0.08945269137620926,
... |
<p>I have been given an excel document with many rows full of numbers, some rows are marked.</p>
<p>Each row represents a case in the clinic, each column represents a research test parameter.</p>
<p>I need to find, what's so special about these marks that make them marked, and it has to be in a unified pattern, so I ... | g63178 | [
0.049998052418231964,
0.051233500242233276,
-0.038970790803432465,
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0.03871387243270874,
0.006431239657104015,
0.06267787516117096,
0.003855320392176509,
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0.015279876068234444,
0.023102685809135437,
0.01... |
<p>I have a simple Text analyzer which generates keywords for a given input text. Till now I have been doing a manual evaluation of it, i.e., manually selecting keywords of a text and comparing them against the ones generated by the analyzer.</p>
<p>Is there any way in which I can automate this? I tried googling a lot... | g63179 | [
-0.007344682235270739,
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0.0020175680983811617,
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0.0027525145560503006,
0.02495989389717579,
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0.01816229708492756,
-0.006772344466298819,
-0.012798466719686985,
0.024399759247899055,
... |
<p>I would like to run a poisson regression and have R calculate incidence rate ratios, much like the irr option for poisson regression in stata.</p>
<p>If anyone can advise how to do this I would be grateful.</p>
<p>Thanks
PS</p> | g37643 | [
0.038286227732896805,
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-0.009858502075076103,
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0.03894759342074394,
0.0440334677696228,
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-0.0342983603477478,
0.018051614984869957,
0.0049514551647007465,
0.008583235554397106,
0.019... |
<p>I am a novice Stata user (forced here from R to conform to coauthor's quirky option choices). I need access to the Pearson residuals from a negative binomial regression. I currently have the regression equations specified in this manner:</p>
<pre><code>xi: nbreg cntpd09 logpop08 pcbnkthft07 pccrunion07 urbanpop pov... | g20711 | [
-0.010702228173613548,
-0.11666061729192734,
-0.006565382704138756,
0.020811909809708595,
-0.026698432862758636,
-0.031372252851724625,
0.017959775403141975,
-0.0156958419829607,
-0.0764150470495224,
0.01921823062002659,
-0.008798688650131226,
0.02461092732846737,
0.01774679869413376,
-0.0... |
<p>Kenward and Roger (1997) proposed an approximation for an $F$-test of fixed effects in a linear mixed-effects model through (1) inflating the estimated variance-covariance matrix of the fixed and random effects and (2) adjusting the degrees of freedom (DF). In their paper they state that, when the approximation is a... | g63180 | [
0.02618638426065445,
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0.0006361762643791735,
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0.03417053818702698,
0.049397557973861694,
0.0011956066591665149,
0.0008072229102253914,
0.04962558671832085,
-0.06905578076839447,
-0.023766864091157913,
0.... |
<p>MAD = Mean Absolute Deviation
MSE = Mean Squared Error</p>
<p>I've seen suggestions from various places that MSE is used despite some undesirable qualities (e.g. <a href="http://www.stat.nus.edu.sg/~staxyc/T12.pdf">http://www.stat.nus.edu.sg/~staxyc/T12.pdf</a>, which states on p8 "It is commonly believed that MAD ... | g39930 | [
0.0212041474878788,
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0.010611242614686489,
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0.026566285640001297,
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-0.03826971352100372,
0.09384524077177048,
-0.005449711810797453,
0.1531762182712555,
0.0... |
<p>When the null hypothesis is simple (i.e., has only distribution of the sample) and the only distribution of the sample is continuous, the p-value can be shown to be uniformly distributed over (0,1).</p>
<p>When the null hypothesis is composite (i.e., has more than one sample distributions), is the p-value still uni... | g41732 | [
0.06898500770330429,
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-0.02045869454741478,
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0.012535050511360168,
0.0014011410530656576,
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0.06569754332304001,
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-0.04726126044988632,
-0.008523405529558659,
-0.0371754951775074,
0.03378816694021225,
0... |
<p>Suppose I am using a standard inhibition model to find biochemical parameters that fit my data. The equation is:</p>
<p>$y = \frac{A}{{1 + \exp \left( {\ln \left[ S \right] - \ln IC_{50}} \right)}} $</p>
<p>where $\left[ S \right]$ is the concentration of my inhibitor and $IC_{50}$ is the concentration of my inhib... | g41773 | [
0.0402769036591053,
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-0.014343537390232086,
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0.03128739073872566,
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-0.03427394852042198,
-0.008880390785634518,
0.005830655340105295,
-0.00025844023912213743,
0.03428953140974045,... |
<p>I am looking at a study that analyzes the effect of an infrastructure index on infant mortality and child mortality rates. The database has (asset) quintile level data for 47 different countries (from surveys that used the same methodology in all countries, althought they took place @ different years), thus there ar... | g20712 | [
-0.007678568828850985,
0.016998479142785072,
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0.045633941888809204,
0.00650615431368351,
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0.010883611626923084,
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-0.011576342396438122,
0.007117146160453558,
-0.021173324435949326,
0.07791800051927567,
0.0... |
<p>I have been reading up on how to calculate variance for different situations and the following has me confused…..</p>
<p>If I take a number of samples (e.g. choose 5 kids in a class and ask them how many pets they have), each time I go into a class and choose 5 kids I am going to get a different mean number of pet... | g63181 | [
0.012760097160935402,
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0.011287044733762741,
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0.03318474069237709,
0.006676158402115107,
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0.03534872084856033,
0.006650747265666723,
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0.01711302250623703,
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0.... |
<p>N random points in a ball in $\mathbb{R}^n$ induce a
<a href="http://en.wikipedia.org/wiki/Voronoi_diagram" rel="nofollow">Voronoi splitting</a>
or <a href="http://en.wikipedia.org/wiki/Tessellation" rel="nofollow">tessellation</a>.<br>
Is there a way of random-generating points
so that the volumes of the Voronoi ce... | g20717 | [
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0.04030832648277283,
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-0.041256193071603775,
0.016990983858704567,
-0.021088406443595886,
-0.03788183629512787,
0.008081525564193726,
-0.02306571789085865,
0.009818222373723984,
0.03459359332919121,
0.02... |
<p>is there a way to fit a specified distribution if you are only given a few quantiles? </p>
<p>For example, if I told you I have a gamma distributed data set, and the <strong>empirical</strong> 20%, 30%, 50% and 90%-quantiles are, respectively:</p>
<pre><code> 20% 30% 50% 90%
0.3936833 0.489... | g63182 | [
0.021082811057567596,
-0.042318642139434814,
-0.023740597069263458,
-0.051133014261722565,
0.018849629908800125,
0.0026521501131355762,
-0.013513762503862381,
-0.040408410131931305,
-0.055911384522914886,
-0.003902534954249859,
-0.03166212886571884,
-0.024877149611711502,
0.02693709917366504... |
<p>I am currently undertaking forecasting of energy sales (kWh) for our industrial customers. From historical data gathered from 1993 to 2013, a graph of price per kwh against sales kwh shows a positive relationship. Going ahead to generate the model yielded a positive coefficient of price with energy sales. The other ... | g63183 | [
-0.002953684190288186,
-0.016058119013905525,
-0.036800578236579895,
0.013156800530850887,
0.0012659626081585884,
-0.0063347904942929745,
0.011405618861317635,
-0.023329278454184532,
-0.08755035698413849,
-0.027408352121710777,
0.041722316294908524,
0.0343218632042408,
0.0360383577644825,
... |
<p>I have a dataset with around 9000 cases, I'm running a factor analysis and I have found that 1100 cases are identified as being a multivariate outlier. Is it alright for me to got ahead and delete it?</p> | g63184 | [
0.023174861446022987,
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0.028925908729434013,
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0.01686958782374859,
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-0.008877590298652649,
0.005583362653851509,
0.019422680139541626,
0.026674050837755203,
-0.021801326423883438,
... |
<p>My data was collected using <a href="http://en.wikipedia.org/wiki/Randomized_response" rel="nofollow">Randomized Response Technique</a>. So I have additional variability into the data. I have a binary response variable. Should I customize a logit link function to incorporate the known probabilities of Randomized Res... | g20720 | [
-0.04140043258666992,
-0.010563562624156475,
-0.010655119083821774,
-0.0271476898342371,
-0.015599092468619347,
-0.031778011471033096,
0.016873886808753014,
-0.01185867190361023,
-0.013618373312056065,
-0.091524638235569,
0.021210139617323875,
0.006175164598971605,
0.013218209147453308,
0.... |
<p>I have monthly data at physician level (sales and marketing activity data for last 12 months for 3000 physicians). I want to find out the impact of marketing activity on sales. There are other covariates and independent variable is continuous. How should I approach the model?</p> | g63185 | [
-0.017035724595189095,
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0.08114404231309891,
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0.0100467000156641,
-0.0034520691260695457,
0.06584866344928741,
0.03894279524683952,
0.01923457533121109,
0.010... |
<p>First of all, what is the difference between the Mann-Whitney and Wilcoxon rank-sum test? How do I choose between the two? I know the latter is implemented in R, is there a way to do the Mann-Whitney test? Is there a way I can include my (very large) datasets in this post so you can get an idea of what I'm trying to... | g49665 | [
0.010646154172718525,
0.0000607851761742495,
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0.04693491384387016,
0.0032618523109704256,
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-0.012824326753616333,
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0.007814050652086735,
0.013852826319634914,
... |
<p>Can some one help me to understand the right scale of measurement to use in sign test as well as in signed rank test? I read a certain book it says nominal scale is used in sign test while ordinal scale is used in signed rank test, the other online material says ordinal scale is used in both sign test and signed ran... | g63186 | [
-0.01936778426170349,
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0.023160681128501892,
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0.04406482353806496,
0.07121764123439789,
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-0.0... |
<p>I am trying to create a record linkage system using the fellegi-sunter model.I am following this paper <a href="http://digital.library.okstate.edu/etd/SHIN_okstate_0664M_10668.pdf" rel="nofollow">http://digital.library.okstate.edu/etd/SHIN_okstate_0664M_10668.pdf</a>. I am not understanding clearly how to calculate ... | g9397 | [
-0.031020764261484146,
-0.012791731394827366,
-0.03495773673057556,
0.010400816798210144,
-0.0409369021654129,
0.010502812452614307,
0.015194683335721493,
0.029552331194281578,
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-0.0851331427693367,
0.04684118926525116,
0.014543990604579449,
0.04... |
<p>I am trying to <code>createFolds</code> function in <code>caret</code> to use k-fold cross-validation in R. But I came across this warning:</p>
<pre><code> Warning messages:
1: In foldVector[which(y == dimnames(numInClass)$y[i])] <- sample(seqVector) :
number of items to replace is not a multiple of replacemen... | g18909 | [
0.015721699222922325,
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0.011970813386142254,
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0.0014696342404931784,
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0.041059356182813644,
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0.0019720850978046656,
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0.006177005358040333,
0.03017468750476837,
... |
<p>I have to do forecasting of sales that is how much sales of a product is going to happen in a particular store.
I have time series data for last two years and doing forecasting for 2014.
The variables are promotion flag ( Yes/ No ), promotion period, location in a store, price discount.
These all are categorical var... | g63187 | [
-0.04058747738599777,
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0.016908913850784302,
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0.037028633058071136,
0.05891377851366997,
0.07910972088575363,
0.0498... |
<p>When evaluating clustering methods which do have a definition for noise points (like dbscan), how noise will affect evaluation?</p>
<p>Consider a clean dataset like well known Iris dataset. There is no noise in it. In evaluation metrics like homogeneity should we remove noise labels and then compute the metric?</p>... | g20728 | [
-0.0031193748582154512,
0.00615746108815074,
0.012826015241444111,
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0.05464163422584534,
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0.0227050818502903,
0.06616156548261642,
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0.02729068510234356,
0.035779859870672226,
0.03999985754489899,
0.07602322846651077,
0.028508... |
<p>This question is based on the example 11.1 out of the book Applied linear statistical models of Kutner, Nachtsheim, Neter and Li. You can find the <a href="http://www.stat.lsu.edu/exstweb/statlab/datasets/KNNLData/CH11TA01.txt" rel="nofollow">data here</a>.</p>
<p>First they calculate a simple linear model:</p>
<p... | g63188 | [
0.030610868707299232,
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-0.010551548562943935,
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0.04495932161808014,
0.021550141274929047,
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-0.0669364333152771,
-0.005263318307697773,
-0.0260179340839386,
0.07802689075469971,
0.03610160946846008,
-0.022... |
<p>I would like to test $H_{0} :$ $\mu_{1} = \mu_{2}, \ \sigma_{1}^{2} = \sigma_{2}^{2}$ vs $H_{0} :$ $\mu_{1} \neq \mu_{2}, \ \sigma_{1}^{2} \neq \sigma_{2}^{2}$<br><br>Is there a test statistic that would allow me to detect both differences in the mean and differences in the variance? Is there a way that I could poss... | g63189 | [
-0.00021631212439388037,
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0.018288347870111465,
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0.018336644396185875,
0.010503864847123623,
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-0.03137081116437912,
-0.019906535744667053,
0.029574040323495865,
-0.025533372536301613,... |
<p>Suppose I have realized n predictions $p_1, \dots, p_n$ using a classification method (for instance a logistic regression or a linear discriminant analysis). Each prediction is associated with a standard error $\sigma_1, \dots, \sigma_n$.</p>
<p>I want to estimate the mean prediction and a confidence interval for i... | g63190 | [
-0.012279006652534008,
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0.012787653133273125,
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0.003990307915955782,
0.031173404306173325,
0.059605520218610764,
... |
<p>I need to make a Kaplan Meier plot with a risk table beneath it. Otherwise stated, I need a table of the number of subjects at risk at different time points aligned below the figure. I found a <a href="http://www.r-bloggers.com/kaplan-meier-survival-plot-with-at-risk-table/" rel="nofollow">website</a> that explains ... | g20731 | [
-0.016257110983133316,
0.005667792167514563,
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-0.012395127676427364,
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-0.008264747448265553,
0.03509152680635452,
0.011288449168205261,
0.03188149631023407,
0.... |
<p>I have two samples of $n=10$ with the following values</p>
<p>Sample 1:</p>
<ul>
<li>Mean = $3$ </li>
<li>$s_{d} = 0.4$</li>
</ul>
<p>Sample 2:</p>
<ul>
<li>Mean = $3.35$ </li>
<li>$s_{d} = 0.3$</li>
</ul>
<p>but the observations of both samples are unknown and I want to know the common $s_{d}$ to calculate $t_... | g49287 | [
0.02519601210951805,
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0.03718666359782219,
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0.036525167524814606,
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0.004298089072108269,
-0.013089679181575775,
0.044129837304353714,
0.027795126661658287,
-0.... |
<p>If I do the PCA on the whole dataset I get 7 components that can explain 90% of the variance, if I split the dataset into 2 (sorted by time), the number of significant components in the first half goes to 5 (with 15 variables present in one or more components) and in the second half goes to 8 (with 21 variables pres... | g20734 | [
0.008119946345686913,
0.008370005525648594,
0.0032744454219937325,
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0.026982620358467102,
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0.05189748853445053,
0.023803558200597763,
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-0.033071842044591904,
0.006324159447103739,
0.031615763902664185,
0.000022536891265190206,
... |
<p>This question is a continuation of the discussion here:</p>
<p><a href="http://stats.stackexchange.com/questions/31690/how-to-test-the-statistical-significance-for-categorical-variable-in-linear-regr">How to test the statistical significance for categorical variable in linear regression?</a></p>
<p>Following Macro... | g20736 | [
0.047022804617881775,
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-0.012603278271853924,
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0.04621340334415436,
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-0.006121756974607706,
0.033613793551921844,
0.05300910398364067,
... |
<p>Let's say I have a logistic regression model which predicts whether a consumer will buy an item based on about 10 consumer characteristics. </p>
<p>$$\begin{array}{rcl}Buy &=& B_0 + B_1\times Gender + B_2\times CreditType + B_3\times Education + B_4\times OwnsHome \\\phantom{Buy} && + B_5\times CarM... | g63191 | [
-0.016715992242097855,
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0.03246132656931877,
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0.011090866290032864,
0.024941690266132355,
-0.023124821484088898,
0.06676433980464935,
0.01918... |
<p>I'm currently in the process of trying to understand the paper <a href="http://www.stanford.edu/~hastie/Papers/glmnet.pdf" rel="nofollow">Regularization Paths for Generalized Linear Models via Coordinate Descent</a> by Friedman et al. with regard to the regularization of logistic regression. Unfortunately, I was not... | g63192 | [
0.030206140130758286,
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0.008484864607453346,
0.0457734577357769,
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0.04963931068778038,
0.05060358718037605,
-0.001... |
<p>I saw <a href="http://i.imgur.com/6kVrT.png">this plot</a> in the supplement of a <a href="http://www.biomedcentral.com/1755-8794/5/28/abstract">recent paper</a> and I'd love to be able to reproduce it using R. It's a scatterplot, but to fix the overplotting there are contour lines that are "heat" colored blue to re... | g20737 | [
0.03920944780111313,
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0.005788655020296574,
0.0503157377243042,
0.011294838041067123,
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0.00... |
<p>Can we proof that two principal component scores are not equal or one is better than the other in terms of variation? For example, the 1st principal component score is defined as $z_1 = a_{11}(y_1 - \mu_1) +...+ a_{1p}(y_p - \mu_p)$ with the eigenvalue $\lambda_1$. We all know that the proportion of total population... | g48520 | [
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0.03465208038687706,
0.008935933001339436,
0.06340713798999786,
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0.04782... |
<p>I'm reading a paper that does not report the coefficients from two OLS regressions. In both cases there is 1 response variable and 1 predictor variable. The predictor variable is the same in both cases. I know the subject matter of the paper well, which leads me to believe that the means of the slopes are almost ce... | g63193 | [
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0.035856638103723526,
0.03473702445626259,
-0.... |
<p>I am using <code>rank(a, ties.method="max")</code> to rank a. But I am not quite sure what does <code>ties.method="max"</code> do. Can you please help?</p> | g20 | [
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<p>I am evaluating results of an A/B-style experiment where we have different groups of people that can perform a target action. They can do the target action as many times as they want, but most people don't do this very often (poisson distribution). </p>
<p>I'm interested in how I can best calculate the statistical ... | g63194 | [
-0.04857569560408592,
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0.007580876350402832,
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0.06385435163974762,
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0.016910158097743988,
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0.0018677696352824569,
0.01... |
<p>This is a somewhat typical a/b test setup. However the proportions that I'd like to test for differences are very small (< 1%). Consequently a 20% difference, which is meaningful, is 0.001. That's a small effect size!</p>
<p>A power test of the chi-squared test for differences in proportions (same sample size... | g63195 | [
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0.06333575397729874,
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... |
<p>I built a suggestion system, which provides a list of candidate items to users. As users choose some items from the suggested list, the system remembers those choices, and the next time the system reorder the candidate list so the items that were heavily selected before will appear at the top of the list. So the mor... | g20742 | [
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0.03992040827870369,
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0.06264146417379379,
0.00877214502543211,
0.03985042870044708,
0.028621971607208252,
0.07149409... |
<p>I've been tasked with implementing a visualization something like this one from the New York Times:</p>
<p><a href="http://www.nytimes.com/interactive/2012/08/05/sports/olympics/the-100-meter-dash-one-race-every-medalist-ever.html?hp" rel="nofollow">http://www.nytimes.com/interactive/2012/08/05/sports/olympics/the-... | g41021 | [
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0.09045785665512085,
0.0... |
<p>Data are 2D x-y pairs, both of which have [0-1] possible range. I need to calculate how well these data fit a linear relationship, where the intercept is 0 and the slope is 1. In other words, a "perfect" metric score should be achieved if the data form a straight line between (0,0) and (1,1), and always worse than t... | g633 | [
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0.02897874265909195,
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-0.0011324746301397681,
0.03859422355890274,
0.005190208554267883,
0.03406316787004471,
... |
<p>My data has a binary response <code>acc</code>(correct/incorrect), one continuous predictor <code>score</code>, three categorical predictors (<code>race</code>, <code>sex</code>, <code>emotion</code>) and a random factor <code>subj</code>. All predictors are within-subject.</p>
<p>By selecting the random effects fi... | g18104 | [
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0.042926568537950516,
0.01256555039435625,
-0.... |
<p>My training data looks like this:</p>
<p><code>
win gender age country ...
1 F 20 US ...
1 M 21 CA ...
0 M 22 CA ...
0 M 20 CN ...
</code></p>
<p>Now I want to apply <code>Logistic Regression</code> to predic... | g63196 | [
-0.003266334068030119,
-0.025389518588781357,
-0.0013171164318919182,
-0.015575768426060677,
0.001617864123545587,
-0.02740469202399254,
0.029048902913928032,
-0.0043946607038378716,
-0.061220258474349976,
-0.04344584047794342,
0.018536439165472984,
0.04207449033856392,
0.08564278483390808,
... |
<p>I have two groups of samples ($A$, $n=100$ and $B$, $n=30$). For each groups we measured whether a trait is present or absent in each sample (0 or 1), resulting in frequency of "ones" for each trait. This we have done for 17 traits. Each individual trait can be easily compared using Chi square and we found that 3 ou... | g20746 | [
0.00023797810717951506,
-0.01373785175383091,
0.015165610238909721,
-0.0485130250453949,
0.027215436100959778,
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0.008613849990069866,
0.04968417435884476,
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0.012291992083191872,
0.03261546045541763,
0.00657972926273942,
-0.03136380761861801,
0.01... |
<p>I am doing research on organisational change and looking at how certain types of change (e.g. closures of offices, layoffs, investment on activities/functions) have affected seven psychological variables (commitment, trust in leaders, procedural fairness, perception of organisational support, etc.). </p>
<p>Now, I ... | g63197 | [
-0.0007495497702620924,
-0.014346055686473846,
-0.027179371565580368,
-0.022285107523202896,
0.03537016734480858,
-0.0006901594460941851,
0.040022287517786026,
0.04522375389933586,
-0.01757289655506611,
0.028237702324986458,
0.00320229260250926,
0.018970182165503502,
0.0007177059887908399,
... |
<p>I have a situation like this: </p>
<blockquote>
<pre><code> Sample1 Sample2 Sample3 .....
Gene1 0.38 0 0.13 .....
Gene2 0.11 0.12 0 .....
Gene3 0.55 0 0.9 .....
..... ..... ..... ..... .....
</... | g63198 | [
0.022188175469636917,
-0.011838342063128948,
-0.009328915737569332,
-0.04511651024222374,
-0.007750317454338074,
-0.08158235251903534,
-0.00719485292211175,
0.024811863899230957,
-0.034083425998687744,
-0.0007160301320254803,
-0.003645317628979683,
0.057231586426496506,
-0.005097284913063049... |
<p>I am designing a questionnaire for my dissertation. I am in the process of validating the questionnaire I have applied a Cronbach's alpha test to the initial sample group. The responses to the questionnaire are on a Likert scale; can anyone suggest any further tests to apply to help test its validity. I am not an ... | g20752 | [
0.027534032240509987,
-0.052046503871679306,
0.0036494657397270203,
-0.04120872542262077,
-0.009664155542850494,
0.010368406772613525,
0.002650331938639283,
0.05190970003604889,
0.012490401975810528,
0.00594768300652504,
0.032345015555620193,
-0.0016201415564864874,
-0.005296276416629553,
... |
<p>We are often interested in estimating the limiting distribution of a parameter in situations where the data exhibit dependence within clusters. For example, a study of the effects of a household-level treatment on household-level outcomes must contend with the possibility that households within villages will have co... | g20753 | [
-0.047845132648944855,
0.014662152156233788,
-0.020669000223279,
-0.04979545250535011,
0.01587158441543579,
0.005498765967786312,
0.019002847373485565,
-0.001889779232442379,
-0.034361910074949265,
0.008025371469557285,
0.019489500671625137,
-0.005376540590077639,
-0.01411193422973156,
0.0... |
<p>I know about $r^2$ tells you about the amount of variation that can be explained by the predictor variables. I have run a model in which the rsquare has value 0.3010 but has false positive rate of around 15.60%. So this model which is logit in nature predicts 84% cases right. I want to know two things:<br>
1) Is thi... | g20757 | [
0.005695598665624857,
0.0029286460485309362,
-0.006571308244019747,
0.04913341626524925,
0.007907507009804249,
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0.028884997591376305,
-0.004148656502366066,
-0.034250129014253616,
-0.014496439136564732,
-0.0047269766218960285,
0.06651139259338379,
0.04638689011335373,
... |
<p>I have heard the terms training and validating a model. I know that we select variables which are most statistically significant and we look for other things like multicollinearity. My question is:</p>
<p>what does traning a model involves more than this ? </p> | g63199 | [
-0.012616046704351902,
0.07247553020715714,
0.005974458064883947,
-0.015642326325178146,
0.06514911353588104,
-0.012359018437564373,
0.005930393468588591,
0.07062364369630814,
0.01220439001917839,
0.015874354168772697,
-0.04793775454163551,
-0.021937040612101555,
0.0893227607011795,
0.0127... |
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