question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I have a graph that I did in SPSS </p>
<p><img src="http://i.stack.imgur.com/FGTir.png" alt="enter image description here"></p>
<p>I would like to replicate this in R. </p>
<p>The data file is here: <a href="http://dl.dropbox.com/u/22681355/sendergraphR.csv" rel="nofollow">http://dl.dropbox.com/u/22681355/senderg... | g62318 | [
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<p>I have the graph like this:
<img src="http://i.stack.imgur.com/loNKw.png" alt="enter image description here"></p>
<p>R code for generating it is:</p>
<pre><code>DF <- data.frame(date = as.Date(runif(100, 0, 800),origin="2005-01-01"),
outcome = rbinom(100, 1, 0.1))
DF <- DF[order(DF$DateVari... | g19323 | [
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<p>My dependent variable is measured on a 4 point likert scale and independent variable is measured on a 7 point likert scale. Is it appropriate to run regression analysis on such data with varying lengths of likert scale, especially a 4 point likert scale against a 7 point likert scale. </p> | g62319 | [
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<p>If I have the following model <code>y~s*dist(a,b)</code> where <code>s</code> is a constant and <code>dist</code> is a given distribution (assume that the parameters <code>a</code> and <code>b</code> cannot be transformed to account for scaling), how do I model this in JAGS?</p>
<p>I get the following error: <stron... | g19327 | [
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<p><em>I'm a student in humanities---maths aren't my strong points, but I'm trying hard, so bear with me please:</em></p>
<p>I have a survey with seven questions (A to G) and a population divided in four categories (1 to 4). The answer to each question may be True or False.</p>
<p>First, I made a calculation of the t... | g38344 | [
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<p>I was given data to analyze for a study looking at the effects of a treatment on iron levels at four different time points (before treatment, the day treatment ended, 4 weeks after treatment, and 2-4 months after treatment). There is no control group. They are looking to see if there are significant increases in i... | g62320 | [
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<p>I am having some problems in modifying Procrastinator's code that assesses the fit of the Inverse Gamma distribution to some randomly generated data. I am refering to the code appearing in the following link:</p>
<p><a href="http://stats.stackexchange.com/questions/33616/fixing-pearsonfitml-to-fit-to-a-pearson-v-di... | g38346 | [
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<p>I have a set of samples from measurement. It can be expressed as random variable $Z = X + Y$. So that $Z$ is observable, but $X,Y$ is unobservable. According to prior knowledge and histogram of $Z$, I can assume that $X$ following exponential distribution with a manual selected parameter. The estimation of probabili... | g62321 | [
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<p>Should you say a factor is associated with a disease or disease risk? For example, which is better to say:</p>
<ol>
<li>Smoking is associated with lung cancer</li>
<li>Smoking is associated with lung cancer risk</li>
</ol> | g62322 | [
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<p>I saw a method for dimensionality reduction for the squared exponential covariance function (not ARD) whereby one uses a $G\times D$ projection matrix $P$ ($G < D$, $D$ = dimension of the inputs) such that the squared distances are calculated in a lower dimensional space. E.g. the kernel function
$$K(x, x') = c ... | g38353 | [
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<p>I have a data set of two variables as class and test score. Where class is a classification made by experts and test score ranges 0-10. The data set looks like:</p>
<pre><code>Class score
1 5.61
1 4.23
2 6.78
3 8.34
2 7.42
3 9.59
</code></pre>
<p>How can I find the bound... | g62323 | [
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<p>I am having a dreadful time making progress with the following problem, and would greatly appreciate any pointers you had.</p>
<p>The problem states that a device's risk of failure within 8 hours of activation, X, varies from day to day according to the probability density function $f(x) = 20(1-x)/9$ for $0.1 < ... | g38354 | [
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<p>I am trying to replicate a colleague's work and am moving the analysis from Stata to R. The models she employs invoke the "cluster" option within the nbreg function to cluster the standard errors.</p>
<p>See <a href="http://repec.org/usug2007/crse.pdf" rel="nofollow">http://repec.org/usug2007/crse.pdf</a> for a fai... | g38356 | [
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<p>I believe I need to run a mixed-effects ANCOVA, and I am having difficulty, presumably, because I have missing data in one of my fixed effects or an incomplete design.</p>
<p>I have a random grouping variable, <code>abs.id</code>, two categorical variables, <code>leaf.species</code> and <code>cond.time</code>, and ... | g62324 | [
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<p>I am trying to learn a logistic regression classifier using glm on a dataset of <20 features, but lots of samples. One of the features is a very strong predictor. As a result, the trained model is predicting extreme probabilities of 1.0 and 0.0 on majority of test data. Although the model converges, I get repeate... | g62325 | [
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<p>Still learning basic syntax in R. Basic example code is provided below.</p>
<p>I know how to call consecutive rows but what if, for example, I wanted the 1st and 3rd row? Or better yet, since that is easily called by w[-2,] in this example, what if the data set was larger and I had the need to investigate the 3rd,... | g38357 | [
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<p>I'm a bit lost at the results part of my thesis. I have conducted an generalized maximum likelihood (GML) univariate test with Y variable: dependent variable
one X variable: independent (consists of 2 conditions)</p>
<p>I have a lot of covariates to control for. So i performed different ANOVA's with just one covari... | g62326 | [
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<p>Having read about logistic regression, I understand that the probabilities of the success of the DV, <code>P(Y=1)</code>, do not necessarily grow the same at every level of the independent variable. This is why you can't interpret the coefficients right away like for OLS, saying an increase in one unit of <code>x1</... | g62327 | [
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<p>I'm looking for a way to run a repeated-measures multiple regression in R, which would take care of sphericity - either by applying some corrections (such as Huynh-Feldt), or by avoiding the problem in some other way.</p>
<p>I have 2 factorial repeated measure variables: 3- and 2-level (<code>roi_ant</code>, <code>... | g62328 | [
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<p>I'm a biologist trying to verify that the age, gender, and family group of my samples from a population of whales is representative of the population, in order to make inferences in the discussion. I've been in the field a long time and cannot remember what tests I use to compare goodness of fit in a known populatio... | g62329 | [
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<p>I am using the data <code>veteran</code> from <code>R</code> package <code>survival</code>. </p>
<p>How can I diagnose the normality assumption about <code>time</code>? Should I need to perform a linear regression to measure the dependency of <code>time</code> on <code>age</code> and <code>karno</code>? </p>
<p>... | g62330 | [
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<p>I am looking for literature (or a solution if there is an easy one) on the asymptotic distribution of deterministic terms in linear regression models when the process is unit-root non-stationary I(1).</p>
<p>In particular the model I am interested in (set $\alpha=1$ so the process is I(1)):</p>
<p>$y_t = \alpha y_... | g19338 | [
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<p>I'm trying to write a seasonal ARIMA model ARIMA(1,0,3)(1,2,0) period 5 mathematically but I don't seem to be able to follow what this resource is saying <a href="https://www.otexts.org/fpp/8/9/" rel="nofollow">otexts arima</a></p>
<p>The example they use is ARIMA(1,1,1)(1,1,1)4 so it makes it very hard for me to f... | g19339 | [
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<p>I was hoping to get some input on the best way to test some data that I have collected (using SPSS). </p>
<p>In short, respondents make an evaluation at time 1, then complete a distractor task, and then complete an evaluation at time 2 (DV is a 1-7 scale). It is a 2x2 between subjects design where 2 variables are m... | g19341 | [
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<p>My knowledge of statistical methods is so poor, so I don't know exactly what is the best statistical method to opt in my case.</p>
<p><strong>Ultimate goal: These parameters(A, B and C) could affect parameter D. I want to know whether they do affect it? What is the correlation between each of the parameters and par... | g62331 | [
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<p>I am conducting research investigating two different groups of women: one group of Short-Stature Women (SSW) and another with Non-Short Women (NSW). We have the hypothesis that SSW has an inaccurate auto-perception of their current body size (CBS). We assessed CBS with a figure rating scale, consisting of 9 differen... | g62332 | [
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<p>I have data in a 15d-space and want to evaluate closeness between samples of instances. As i dont have any assumptions on the distribution of the data I prefer Bhattacharyya coefficients over Mahanolobis distance.</p>
<p>But as my samples are pretty small, I am unsure whether Bhattacharyya coeficients will return r... | g62333 | [
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<p>I need to estimate the function $f$ in the following object $$E[Y|X=x] = a(x)f(x) + b(x)f'(x)$$ with $a(x),b(x)$ known. What would be the optimal strategy to do this? I tried to do the cubic spline approximation with two knots: $f(x) = \theta_0+\theta_1x+\theta_2x^2+\theta_3x^3+\delta_1(x-\xi_1)_+^3+\delta_2(x-\xi_2... | g62334 | [
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<p>I am trying to group procedure codes so that I do not need to hard code thousands of procedure codes and diagnosis codes. I am trying to build a regression to see the effect of percentage of dollars for a provider on total billed amount for a provider on several parameters so that I can find the outliers. The par... | g19346 | [
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<p>I want to create a binary model which predicts whether someone has improved his state. I am testing possible variables as explanatory variables in order to make some recommendations. Now my binary model is quite weak, AUC is around 0.6 and there are hardly any cases predicted above 0.5 in the test set.</p>
<p>Now I... | g62335 | [
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0.027574436739087105,
0.048658... |
<p>I'm using the <code>gee()</code> function from the <code>gee</code> package in R. The problem I'm having is that the 'Maximum cluster size' that I get from the output of the GEE function seems to disagree with what I believe it should be given my data.</p>
<p>Here's a small example, where I have six observations f... | g62336 | [
0.004160725511610508,
-0.024289768189191818,
-0.004028992727398872,
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0.02317052148282528,
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0.006084753666073084,
0.022622641175985336,
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-0.02835555374622345,
0.05564019829034805,
0.018375065177679062,
0.05935855209827423,
-0.013... |
<p>I need to do a number of regressions in SPSS but keep getting error messages. For example - </p>
<p>"There are X cells (i.e., dependent variable levels by combinations of predictor variable values) with zero frequencies."</p>
<p>and</p>
<p>"The log-likelihood value is practically zero. There may be a complete sep... | g62337 | [
0.0028429576195776463,
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0.017210649326443672,
0.051743265241384506,
0.... |
<p>Imagine you have a matrix, where each row represents an individual and each column represents a specific time interval. The entries of the matrix represent events occurring for a given person at a specific interval of time. </p>
<p>Now say we wish to use this representation to build a classifier. So along with the ... | g19348 | [
0.02318134345114231,
0.0004263726877979934,
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0.014511228539049625,
0.06926844269037247,
... |
<p>I need to detect rules in a data set that contains real-valued features. A simplified example of my samples, defined by features a, b, and c, and having class 0 or 1, might look like this:</p>
<blockquote>
<p>2.34, 1, 5.46 => 0</p>
<p>1.23, 0, 7.81 => 1</p>
</blockquote>
<p>For this data set, I am intereste... | g62338 | [
0.026457196101546288,
0.0010843222262337804,
0.0037909322418272495,
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0.013306129723787308,
0.034123413264751434,
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0.07512788474559784,
0.008493596687912941,
0.... |
<p>I'm trying to calculate logistic regression coefficients by defining the log-likelihood function and using maximum likelihood.</p>
<p>In some cases when the initial (start) values I gave to the maximum likelihood were not correct I got wrong results for the logistic regression (different from the ones I get when us... | g45598 | [
0.031834155321121216,
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0.01764237880706787,
0.03528667613863945,
0.03190910816192627,
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0.0061831544153392315,
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0.00851881317794323,
-0.042114872485399246,
0.0354931578040123,
0.06525599956512451,
0.04863... |
<p>I am trying to programatically select a prior distribution from the Gamma family of distributions. The primary criteria that I need to satisfy is that the median of the distribution should be a given value $X$ (i.e. such that it's equally probable to have a parameter value above $X$ or below $X$)</p>
<p>Additionall... | g19351 | [
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0.027828756719827652,
0.025872550904750824,
0.0141673618927598,
0.0... |
<p><strong>Q1:</strong> Is there any Arima (p,d,q) model that can forecast interventions (pulse) itself? I know that I can use <code>xreg</code> or even <code>xtransf</code> arguments as the covariates to include the intervention over the observed time series.</p>
<p>The problem is that I don’t know the new values of ... | g19352 | [
0.00858011282980442,
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0.012310387566685677,
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0.0059676943346858025,
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0.006957906764000654,
0.04497212916612625,
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-0.02331528253853321,
0.012570136226713657,
0.0212565828114748,
0.053952135145664215,
-0.... |
<p>I have a set of survey data related to 20 survey questions. Each of these questions represent a variable (<code>Q1</code>, <code>Q2</code>,...<code>Q20</code>). I created a new variable <code>QCom</code> which measures the response of the survey, and is given by a composite score obtained as the sum of the scores of... | g62339 | [
0.009194597601890564,
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0.048450060188770294,
0.015520757995545864,
0.017758775502443314,
-0.005847073160111904,
-0.023409239947795868,
0.009186121635138988,
-0.00266889831982553,
... |
<p>I'm playing around with network graphs and am wondering how to show that there is:</p>
<ol>
<li>a statistically significant difference in in-degree distribution between nodes for 2 time periods</li>
<li>the in-degree distribution is more equally dispersed among nodes at time 2</li>
</ol>
<p>Now let's say I have a ... | g62340 | [
0.033970676362514496,
0.019079411402344704,
-0.015286893583834171,
-0.05871311575174332,
0.05201253667473793,
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0.05145914852619171,
-0.02979307435452938,
-0.02150697074830532,
0.04150165244936943,
0.007005257532000542,
0.07084257155656815,
0.03165903687477112,
-0.01206... |
<p>I have a setup where the joint posterior is written as:</p>
<p>$$
P(w, \lambda, \phi \vert y) = P(\phi) \times P(w \vert \lambda) \times P(\lambda) \times \prod_{i=1}^{N}P(y_i \vert w_i, \phi, \lambda)
$$</p>
<p>Now $\phi$ and $\lambda$ are modelled as Gamma distributions and the likelihood and prior on $w$ is nor... | g19355 | [
0.07269584387540817,
-0.09691122174263,
-0.0279399361461401,
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0.005527958739548922,
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0.02648184262216091,
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0.049402687698602676,
0.028390785679221153,
0.0615803524851799,
-0.01972012035548687,
0.051122937... |
<p>I have a simple linear regression with age as independent variable and a cognitive scale as dependent variable. Each subject is present only once. </p>
<p>As it is not time-series data and there is no spatial effect, is it correct not to check for autocorrelation? Does a Durbin-Watson result of .23 mean something?<... | g62341 | [
0.020033497363328934,
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0.002201906405389309,
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0.06866144388914108,
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0.01155650895088911,
-0.05629825219511986,
0.04185841605067253,
0.009264483116567135,
0.03475108742713928,
-0.00809... |
<p>I need to find partial derivatives for:</p>
<p>$L=\frac{1}{2}\sum_{i=1}^{n} w_{i}^{2}\sigma_{i}^{2} -\lambda \left( \sum_{i=1}^{n} w_{i} \bar{r_{i}} - \bar{r} \right) -\mu \left( \sum_{i=1}^{n} w_{i}-1 \right)$</p>
<p>with 5 variables, I get 5 partial derivatives $\frac{\partial L}{\partial w_{1}}$, $\frac{\partia... | g62342 | [
0.03965788707137108,
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-0.034483201801776886,
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-0.01748189888894558,
0.0018245645333081484,
0.021748777478933334,
-0.01065448485314846,
0.04... |
<p>This question is related to one <a href="http://stats.stackexchange.com/q/40459/1390">I have already asked</a> but the answer I got that suggests I should adopt a new tack to address my research question.</p>
<p>I repeat the substantive part of the original question to show the features of my particular computer si... | g62343 | [
0.0022633918561041355,
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0.006488851737231016,
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0.04583102464675903,
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-0.00265428121201694,
0.018756745383143425,
0.041701313108205795,
0.017742641270160675,
... |
<p>Working through an example in the Ross Probability textbook. Can someone explain the reasoning behind the answer?</p>
<p>From a group of 7 men, how many committees consisting of 3 men can be formed? what if 2 men are feuding and refuse to serve on the committee together?</p>
<p><strong>Answer, part 1:</strong> Fi... | g38378 | [
0.044904712587594986,
0.027508724480867386,
0.02024652063846588,
-0.0332648903131485,
0.049424249678850174,
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0.015388590283691883,
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0.02514435350894928,
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0.012269466184079647,
-0.016897162422537804,
-0.031... |
<p>this might be a stupid question, but I'll try anyway!</p>
<p>I have a data set from a survey asking about what brands they can remember within the category toys.</p>
<p>The survey participants get to write a single brand in 10 different text boxes. The purpose is to reveal the brand with the greatest top of mind e... | g19360 | [
-0.05033833533525467,
-0.03431358560919762,
0.017903702333569527,
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0.003423186717554927,
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0.02638123370707035,
-0.0006061976891942322,
0.05476973205804825,
-0.0225412268191576,
0.09389928728342056,
0.046... |
<p>I am using earth package for the following data.</p>
<pre><code>x <- c(127, 128, 255, 256, 511, 512, 600, 700, 800, 900, 1000, 1023, 1100,
1200, 1300, 1400, 1500, 1600, 2047, 2048, 2100, 2200, 2300, 2400, 2500,
2600, 2700, 2800, 3000, 3100, 3200, 3300, 3500, 4063, 4064, 4100, 4200,
5200, 540... | g62344 | [
-0.04902084544301033,
0.006128646433353424,
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0.0008400726364925504,
0.049103718250989914,
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0.04512220621109009,
0.09986153244972229,
0.0... |
<p>I have a linear model (with seasonal dummy variables) that produces monthly
forecasts. I'm using R together with the 'forecast' package:</p>
<pre><code>require(forecast)
model = tslm(waterflow ~ rainfall + season, data = model.df, lambda = lambda)
forec = forecast(model, newdata = rainfall.df, lambda = lambda)
</co... | g39127 | [
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0.0035332615952938795,
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0.029042992740869522,
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-0.015400579199194908,
-0.02061876468360424,
0.021003350615501404,
0.030493086203932762,... |
<p>Despite several attempts at reading about bootstrapping, I seem to always hit a brick wall. I wonder if anyone can give a reasonably non-technical definition of bootstrapping?</p>
<p>I know it is not possible in this forum to provide enough detail to enable me to fully understand it, but a gentle push in the right ... | g62345 | [
-0.015137818641960621,
0.08135037124156952,
0.008387015201151371,
0.03785550966858864,
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0.010478553362190723,
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0.042585670948028564,
0.... |
<p>I'm studying the second course in statistics, and now I have a problem to understand $P$-values. Namely, one exercise is the following.</p>
<p>When testing hypothesis $H_0:\mu=\mu_0$ one gets the value of test statistic $z=1.7$. Determine the $P$-value for the alternative hypothesis $H_A:\mu>\mu_0$.</p>
<p>Is i... | g62346 | [
0.018909847363829613,
0.06070374324917793,
-0.02161289192736149,
0.017603633925318718,
0.008512983098626137,
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0.01315839309245348,
0.026561569422483444,
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-0.03810746222734451,
-0.0059047965332865715,
0.026931829750537872,
0.01550842635333538,
0.07... |
<p><img src="http://i.stack.imgur.com/fct3Z.jpg" alt="an example of HMM"> </p>
<p>Given a model (from <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDMQFjAA&url=http://www.cedar.buffalo.edu/~govind/CS661/Lec12.ppt&ei=P-7rUMCqMomP4gTN0oC4DQ&... | g48584 | [
0.06576941907405853,
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0.013079470954835415,
-0.03919626399874687,
0.041132163256406784,
0.0052552130073308945,
0.028841597959399223,
0.013767450116574764,
-0.07532919943332672,
-0.022725772112607956,
-0.0654527097940445,
0.032817985862493515,
0.02578079141676426,
0.01... |
<p>I have a function which I would like to use Taylor expansion and calculate its variance by the following formula:</p>
<p>The formula for variance then becomes
\begin{align}
\operatorname{Var}(f(X))=[f'(EX)]^2\operatorname{Var}(X)+\frac{[f''(EX)]^2}{4}\operatorname{Var}^2(X)+\tilde{T}_3
\end{align}</p>
<p>got the f... | g39161 | [
0.028475185856223106,
0.02807367779314518,
0.0018915529362857342,
0.0024052562657743692,
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0.005390560254454613,
0.017696818336844444,
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-0.02284187637269497,
-0.016635864973068237,
0.03391895443201065,
0.03592241182923317,
0.... |
<p>I calculated 4 factors as latent constructs in a Confirmatory Factor Analysis (I use AMOS). Now I am wondering if it is possible to extract some kind of a factor score like I know it from Exploratory Factor Analysis with SPSS to use those as independent variables in a multiple regression analysis. </p>
<p>Can I use... | g62347 | [
0.0222405306994915,
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0.008430509828031063,
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0.007162061519920826,
0.038061145693063736,
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-0.0385446660220623,
-0.03939509764313698,
0.007257058285176754,
0.04447287693619728,
-0.0158... |
<p>I am new to Cross Validated SE so I am going to try and formulate my question to the best of my ability.</p>
<p>I have a large data set that contains $5$ different fields. The fields are </p>
<pre><code>Gender-(Male, Female),
Age-(0,18],(18,25],(25,45], (45,65], (65,100],
Region - (Northeast, Midwest, South, West)... | g19370 | [
-0.03446061536669731,
0.018008723855018616,
-0.01923939399421215,
-0.0701979473233223,
-0.015466378070414066,
0.030441764742136,
0.005770644638687372,
0.02141893468797207,
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0.0031113161239773035,
-0.01714329794049263,
-0.0008461195975542068,
0.07195843756198883,
-0.01... |
<p>My data has at least 5 variables with a significant response, with one variable having the highest regression co-efficient. I want to find those observations where that variable did <em>not</em> behave as expected, to better understand the other contributors to the outcome.</p> | g62348 | [
0.016789788380265236,
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0.021768717095255852,
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0.09207510203123093,
0.002391434507444501,
-0.016276396811008453,
-0.030614033341407776,
-0.007899741642177105,
-0.018073977902531624,
0.016335001215338707,
0.... |
<p>In my book:
$\mathbf{X}=(X_1,\ldots,X_n)$
$f(\mathbf{x})$ is the joint density, where $f$ is either $f_0 \text{ or } f_1$.</p>
<p>Suppose we want to test $H_0: f=f_0$ or $H_1: f=f_1$. The test, whose test function is</p>
<p>$$\phi(\mathbf{X})=1\text{ if }\frac{f_1}{f_0}\geq k;$$</p>
<p>$$\phi(\mathbf{X})=0 \text{... | g62349 | [
0.032686036080121994,
0.018029669299721718,
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-0.023832596838474274,
0.02930881269276142,
-0.03689702972769737,
-0.02996217831969261,
0.029291316866874695,
-0.062865249812603,
-0.016806960105895996,
-0.0067370678298175335,
-0.012324859388172626,
0.025630973279476166,
0... |
<p>I have two groups of patients which have been followed for up to 5 years.
Using SPSS I would like to find the cumulative survival at 1,2 or 3 years and see if there is a statistically significant difference between the groups at each time point.
This is the equivalent of right censoring at 1,2 or 3 years and runnin... | g62350 | [
0.00850746687501669,
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-0.012190785259008408,
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0.031570546329021454,
0.022903619334101677,
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0.011224289424717426,
0.007722351234406233,
0.04645783454179764,
0.05926418676972389,
0.... |
<p>I need tο use 3D data for training and for that I need to find the Gaussian basis function. I know how to find $f(x,y)$ but how can I find $f(x,y,z)$?</p> | g62351 | [
0.004445859231054783,
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0.014880015514791012,
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0.01172966044396162,
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0.03785640746355057,
0.0044556185603141785,
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-0.05085968226194382,
-0.05259859189391136,
0.0017752574058249593,
0.06207585707306862,
-... |
<p>I'm looking for a Python alternative to R's ETS() from forecast(). </p>
<p>It's my understanding that ETS() is one of the best performing forecasting program and I would like to use it. However I am extremely uncomfortable using R and I already have all my data cleaned and set up in Python.</p>
<p>Does anyone know... | g62352 | [
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0.07514900714159012,
0.040470439940690994,
0.03586414456367493,
0.0... |
<p><a href="http://www.timeuse.org/information/sequence" rel="nofollow">ClustalG</a>, the social science version of <a href="http://www.clustal.org/" rel="nofollow">ClustalX</a>, can use different 'opening' and 'extension' penalties for indels, so that an indel operation can have more weight when it adds the first elem... | g62353 | [
0.0016580779338255525,
0.05688416585326195,
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0.00482018431648612,
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0.02657414600253105,
0.0... |
<p>Main question: "What are the contributing variates to daily movement distances?"</p>
<p>Specifically my question today relates to:</p>
<p>"What is the contribution related to gender, and then within female what are the effects related to those females having young?"</p>
<p>I have multiple readings per animal (hun... | g19375 | [
-0.03178103268146515,
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0.01043028011918068,
-0.057658009231090546,
0.03350149467587471,
-0.0031163953244686127,
0.0745621845126152,
-0.03754711151123047,
-0.047682035714387894,
-0.020861763507127762,
-0.05420965328812599,
0.04217587783932686,
0.0535813644528389,
0.0245... |
<p>So here is what I did, I input the command, <code>davis.mod <- lm(weight ~ repwt, data=Davis)</code>. It's a bi-variate regression that is using reported weight to estimate actual weight. </p>
<p>When i summarized the data, this is what I get. </p>
<pre><code>Call:
lm(formula = weight ~ repwt, data = Davis)
Re... | g62354 | [
-0.018541330471634865,
-0.05422612652182579,
-0.04372227564454079,
-0.04004804044961929,
0.024949731305241585,
0.029538683593273163,
0.038177065551280975,
0.027400344610214233,
-0.06674489378929138,
-0.07273931056261063,
-0.04775317758321762,
0.07499007880687714,
0.03574959188699722,
-0.02... |
<p>I trained a classifier and got the following stats on some test data:</p>
<pre><code> Correctly Classified Instances 1059 95.1482 %
Incorrectly Classified Instances 54 4.8518 %
Kappa statistic 0
Mean absolute error ... | g62355 | [
0.0047681815922260284,
-0.06292001903057098,
0.019688507542014122,
-0.028225528076291084,
0.05880877748131752,
-0.05803684517741203,
0.0605725534260273,
0.032302893698215485,
-0.004501913208514452,
-0.046038560569286346,
-0.015474468469619751,
0.05810263007879257,
0.014415993355214596,
-0.... |
<p>I am using ggplot2 in R to make plots like the following ones:</p>
<p><img src="http://i.stack.imgur.com/mwRYh.png" alt="enter image description here"></p>
<p>The errorbars overlap with each other which look really messy.
How can I separate the errorbars for different indices?
I have used position="dodge" but it s... | g62356 | [
0.013211890123784542,
-0.04598625376820564,
-0.001961029600352049,
-0.02986292727291584,
0.05099307745695114,
0.016666654497385025,
0.018550796434283257,
-0.007136620115488768,
-0.07263471186161041,
0.0093262679874897,
0.05923909321427345,
0.03609556332230568,
0.013358335942029953,
-0.0232... |
<p>Is it possible to implement the Takagi-Sugeno (T-S) fuzzy model using PyBrain ?</p> | g62357 | [
-0.048642098903656006,
0.10089602321386337,
0.003982139751315117,
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-0.05157660320401192,
-0.018521910533308983,
0.0704052746295929,
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0.0032032744493335485,
0.010234430432319641,
-0.05691445991396904,
0.008976299315690994,
0.... |
<p>I have seen that a number of Statistics texts state that in order to get the $1-a$ confidence interval, we have to arrange our $B$ bootstap sample estimators in order statistics:</p>
<p>$$ \theta_{(1)} \leq \theta_{(2)} \leq \ldots \leq \theta_{(B)} $$</p>
<p>Then choose $m= \left[ \left( a/2 \right) B \right]$ wh... | g62358 | [
-0.04488168656826019,
0.03934241086244583,
-0.021900534629821777,
0.04993056505918503,
0.060992199927568436,
0.038468871265649796,
0.07878042757511139,
0.00346673303283751,
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-0.055252522230148315,
-0.0420849472284317,
0.05838601663708687,
0.00031688978197053075,
-0.004... |
<p>Suppose we have $X,Y$ i.i.d. Is there a simplified form of $E[\max\{X,Y\}]$? Is it just $\max\{E[X],E[Y]\}$? That doesn't seem right, because the latter would just be $E[X]$, and it seems like taking a max should increase the expectation.</p>
<p>Here's what I have so far:</p>
<p>$$\begin{align}
E[\max\{X,Y\}] &... | g62359 | [
-0.018272941932082176,
0.04014276713132858,
-0.013194425962865353,
-0.03500974178314209,
0.006856593303382397,
-0.045642103999853134,
-0.031022457405924797,
0.028253184631466866,
-0.022630074992775917,
0.02733970806002617,
-0.04068862274289131,
0.014270245097577572,
0.048246510326862335,
0... |
<p>If I apply ARMA on a stationary differentiated time series and want to make forecasts with this model, the forecast will be on the differentiated values. I need the values to be non-differentiated, is it possible?</p> | g19385 | [
-0.002178956288844347,
-0.037783730775117874,
-0.00026721777976490557,
-0.006891108117997646,
0.023727992549538612,
-0.008858717978000641,
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-0.042191002517938614,
-0.02762383222579956,
0.008718756027519703,
0.012270987033843994,
0.02301449701189... |
<p>Suppose I am comparing the computational time of two algorithms <strong>A</strong> and <strong>B</strong>. They are solving randomized problem <strong>P</strong>. Let's say I solved the problem for seeds $ 1, 2, \dots, n $ with both A and B and got the times:</p>
<p>$ a_1 , a_2, \dots , a_n $ for problem <strong>A<... | g62360 | [
0.04010319337248802,
-0.006808719132095575,
-0.006343727465718985,
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0.013932714238762856,
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0.02627216838300228,
0.047004733234643936,
-0.019019335508346558,
0.04619600251317024,
0.04334082081913948,
0.028595533221960068,
0.06059860810637474,
0.05486... |
<p>I am having confusion and difficulties using <code>glmnet</code> with <a href="http://www-stat.stanford.edu/~tibs/lasso.html">lasso</a> where my outcome of interest is dichotomous. I have created a small bogus data frame below:</p>
<pre><code> age <- c(4,8,7,12,6,9,10,14,7)
gender <- c(1,0,1,1,1,0,1,0,0)
b... | g19390 | [
0.04099341481924057,
-0.03558848053216934,
-0.002334137912839651,
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0.03173086419701576,
-0.040901120752096176,
0.05753174051642418,
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-0.055329710245132446,
0.00493481894955039,
0.057992689311504364,
0.10914850980043411,
-0.02... |
<p><strong>In a nutshell:</strong></p>
<p>Two treatments are thought to result in comparatively different outcomes depending on when they are administered, with one possibly being better for patients who are treated soon after symptom onset, and the other being better for patients who are treated later. </p>
<p>How c... | g62361 | [
0.00712233129888773,
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-0.038546327501535416,
-0.02383124642074108,
0.03098694048821926,
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0.031472012400627136,
0.014804012142121792,
-0.047485463321208954,
-0.00554452883079648,
0.025118404999375343,
0.01846756972372532,
0.04232506826519966,
0.006... |
<p>I have two series of $m$ observations each $n_i,X_i$ where $ i=1,....m$, and a related probability $p$. $n_i$ is large and $p$ is small, so we can assume that $X_i \sim Poi(n_ip)$. What is the maximum likelihood estimator of p in this situation and what is the expectation and variance of the estimator?</p>
<p>Thank... | g19391 | [
-0.010012947022914886,
0.012424889020621777,
-0.004518653731793165,
0.013006418012082577,
-0.05868756026029587,
-0.006750680506229401,
-0.00027584441704675555,
0.0001695351384114474,
-0.01810038834810257,
-0.00825301930308342,
-0.04749780893325806,
0.0023133226204663515,
-0.0496208518743515,... |
<p>I'm studying for some time and I´m trying to do a logistic regression (using GLM in R) and now it´s extremely difficult to know what to do.</p>
<p>I have a binary dependant variable and 15 independent variables. As result of running GLM I've got:</p>
<pre><code>glm(formula = y ~ ., family = binomial(link = "logit"... | g62362 | [
0.002856053411960602,
-0.05971210077404976,
0.006879809778183699,
0.004997223615646362,
0.041025370359420776,
-0.04260214790701866,
0.051092155277729034,
-0.009760034270584583,
-0.07302020490169525,
-0.04904453456401825,
-0.03668668121099472,
0.04975647106766701,
0.029761655256152153,
-0.0... |
<p>I am estimating cross-sectional regressions - fragment:</p>
<blockquote>
<p>lm(rate~liqamih.log+cap.log+F1+F2, data=x)</p>
</blockquote>
<p>of the R code listed below.</p>
<p>F1 and F2 are the coefficients estimates of time series model.</p>
<p>In such case we need to deal with so called "error in variables pr... | g62363 | [
-0.002830282784998417,
-0.052934691309928894,
0.01778639853000641,
-0.09369806945323944,
-0.009360774420201778,
-0.037989530712366104,
0.013193970546126366,
0.010104636661708355,
-0.08517184853553772,
0.03802274540066719,
-0.011555719189345837,
0.03527825325727463,
0.029743671417236328,
0.... |
<p>I need to estimate (using cross-validation), the parameters $\sigma$ and $\lambda$ of the Gaussian kernel:</p>
<p>$K_G(x,y) = \sigma^2 \exp{(-\frac{1}{2\lambda^2}\sum_{i,j}(x_{ij}-y_{ij})^2})$</p>
<p>where $x$ and $y$ are the adjacent matrices of a Markov chain. How can I do that?</p>
<p>Thank you.</p> | g19394 | [
-0.016933917999267578,
-0.037695061415433884,
-0.03300654515624046,
-0.03889692574739456,
-0.007680229842662811,
-0.02201865054666996,
-0.003032122040167451,
0.0036381741520017385,
-0.05286535993218422,
0.08148078620433807,
-0.03254915028810501,
0.08181580156087875,
0.01764923520386219,
0.... |
<p>I am building a logistic regression model and one of my independent variable sis heavily skewed. Is it better to use the ln or the log10? Why?</p>
<p>And how to correct the skewness of a variable that contains a lot of zero values?</p> | g49642 | [
0.005698290653526783,
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0.02029120735824108,
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0.05476176366209984,
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-0.023254165425896645,
0.02964361570775509,
0.03789040073752403,
0.05295939743518829,
0.0... |
<p>I have a set of data where each data consist of $n$ different measures. For each measure, I have a benchmark value. I would like to know how close each data is to the benchmark value.</p>
<p>I thought of using the Weighted Euclidean Distance like this:</p>
<p>$\hspace{0.5in} d_{x,b}=\left( \sum_{i=1}^{n}w_i(x_i-b_... | g62364 | [
-0.0024470495991408825,
0.031021667644381523,
-0.03558703884482384,
-0.07350660115480423,
0.010198418982326984,
0.006476896815001965,
-0.019381241872906685,
-0.01051692757755518,
-0.11687823385000229,
0.025199126452207565,
-0.008094294928014278,
0.01873992197215557,
0.013743815012276173,
0... |
<p>How can I test if two averages of Pearson's correlation coefficients are significantly different?</p>
<p>For instance, I have data pertaining to participants' estimates of certain percentages (e.g. how many percent of US-citizens are taller than 6 feet) in a number of different conditions. </p>
<p>For instance, I ... | g62365 | [
0.0023027800489217043,
-0.05804191902279854,
0.02670193836092949,
-0.003189524170011282,
0.018841058015823364,
-0.01916377805173397,
0.013882389292120934,
0.005075422581285238,
-0.004027109127491713,
0.005280961282551289,
0.07850407063961029,
-0.002780572045594454,
-0.03443118929862976,
-0... |
<p>I believe I have rather simple question but I would like to make it right.<br>
I have already asked question, however I am not sure whether I did everything correct or there is a mistake in the answer (probably the first one, but still I cannot find it).<br>
To make it short:
I would like to check how well my model... | g49882 | [
-0.013438721187412739,
-0.030355365946888924,
0.003995826467871666,
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0.006692582741379738,
-0.04546228423714638,
0.042965251952409744,
0.04625478386878967,
-0.062370769679546356,
0.009252402000129223,
-0.02177816443145275,
0.022107955068349838,
0.08391846716403961,
-0... |
<p>I'm looking for some robust techniques to remove outliers and errors (whatever the cause) from financial time-series data (i.e. tickdata). </p>
<p>Tick-by-tick financial time-series data is very messy. It contains huge (time) gaps when the exchange is closed, and make huge jumps when the exchange opens again. When ... | g22375 | [
0.04305366054177284,
0.015685327351093292,
0.009574971161782742,
0.006302636116743088,
0.005661968141794205,
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0.06257326900959015,
-0.016333330422639847,
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0.01642315834760666,
0.03590766713023186,
-0.009966621175408363,
0.051331520080566406,
-0.0... |
<p>In my dataset we have both continuous and naturally discrete variables. I want to know whether we can do hierarchical clustering using both type of variables. And if yes, what distance measure is appropriate?</p> | g62366 | [
0.05428706109523773,
-0.022369757294654846,
-0.011352055706083775,
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0.0031421533785760403,
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-0.054604899138212204,
-0.002886850154027343,
0.05299350991845131,
-0.04792552441358566,
... |
<p>I am trying to understand censoring in survival analysis and
wondering about how to tell when standard use of censoring breaks down.
In one case, the number of censored patients is fairly high (low death rate), yet the median or mean "survival" time (times of last confirmed observation of the censored patient) among... | g62367 | [
-0.03121913969516754,
-0.02733796089887619,
0.008428828790783882,
0.021532434970140457,
0.009986271150410175,
-0.03023289516568184,
-0.016498077660799026,
0.05694251507520676,
-0.021511588245630264,
0.052449509501457214,
0.01919221505522728,
0.018477197736501694,
0.0778820812702179,
0.0107... |
<p>I hope I am at the right place, I was pointed here for further feedback from <a href="http://stackoverflow.com/questions/7311372/merging-data-from-many-files-and-plot-them">stackoverflow</a>.<br>
I would like to ask you, whether it makes sense to you what I am trying to do in order to optimize my model.</p>
<p>Here... | g19398 | [
0.005816969089210033,
-0.015148613601922989,
-0.02789442241191864,
-0.04497750103473663,
0.009934380650520325,
-0.028360210359096527,
0.029348216950893402,
-0.010492296889424324,
-0.08106538653373718,
-0.003800892038270831,
0.008246230892837048,
-0.00026069468003697693,
0.13317911326885223,
... |
<p>Suppose I have drawn n samples from a population of known mean and variance ( for example, a normal distribution with mean zero and variance 1.0 ).</p>
<p>I then calculate the mean and standard deviation of the sample.</p>
<p>How do I calculate the pdf of these sample values, given that I know the population value... | g19399 | [
0.006430062931030989,
-0.038658589124679565,
-0.0008081431151367724,
-0.05705283582210541,
-0.03143874555826187,
-0.013222063891589642,
-0.019902793690562248,
0.051688194274902344,
-0.02075774595141411,
-0.0020766921807080507,
-0.022637581452727318,
-0.04079563915729523,
0.042781781405210495... |
<p>I have a data set comprising of responses from approximately 385 people on several variables such as their shopping habits, mode of transport to the shopping centre etc. I want to do Pearson correlation on the variables (by age, gender, income level etc. of the respondents).</p>
<p><strong>Is there any rule that s... | g39327 | [
0.006228443700820208,
-0.01480645127594471,
0.0022715767845511436,
-0.07404875010251999,
0.00012704348773695529,
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-0.022160781547427177,
0.010642130859196186,
0.007057403679937124,
-0.03150754049420357,
0.03813224285840988,
-0.036044374108314514,
-0.0018192637944594026,... |
<p>I have a data set of $\approx$100 individuals showing pulse rate before exercise, pulse rate after exercise, sex, smoker status, weight etc. for each individual.</p>
<p>I've been asked to select an individual at random to test whether <strong>their</strong> sex and smoker status are independent, with a hint that I ... | g62368 | [
-0.02303735911846161,
-0.01994752325117588,
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-0.00887380912899971,
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0.0017948111053556204,
0.026640109717845917,
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0.003256489522755146,
-0.010737399570643902,
0.06956173479557037,
0.012592331506311893,
... |
<p>Ratios of two normally distributed variables (e.g X/Y) have no moments (e.g. means and variances) because Y can have zero values. However, lognormal variables have no zero values. How can I calculate the mean and variance of the ratio of two lognormal variables?</p> | g62369 | [
-0.018580244854092598,
-0.017649352550506592,
-0.01176136452704668,
-0.03663052245974541,
0.032648272812366486,
-0.0033146427012979984,
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-0.0021449336782097816,
0.0028548664413392544,
-0.03126530349254608,
-0.034496575593948364,
0.008298012427985668,
-0.04253493994474411... |
<p>Given an unknown classifier, could someone make assumptions for the linearity of this model from the fact that</p>
<p>$$y=\left\{
\begin{aligned}
1 &\;\mathrm{if}\;& p(y=1\,|\,x) \geq 0.5 \\
-1 &\;\mathrm{otherwise}
\end{aligned}
\right.$$
?</p>
<p>Is that the reason we conclude logistic regression is ... | g34431 | [
-0.003035456407815218,
-0.033891718834638596,
-0.003186866408213973,
-0.013606776483356953,
0.05951233208179474,
-0.036074262112379074,
0.03811412677168846,
-0.004890305455774069,
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-0.018851235508918762,
-0.024694232270121574,
0.0839712992310524,
0.010175811126828194,
... |
<p>I am trying to test the significance of the difference between two populations.</p>
<p>Here is a link to the population 1 data: <a href="http://pastebin.com/914mCRqA" rel="nofollow">http://pastebin.com/914mCRqA</a></p>
<p>and population 2 data: <a href="http://pastebin.com/PmDgLLAb" rel="nofollow">http://pastebin.... | g37444 | [
-0.051271963864564896,
-0.014057375490665436,
-0.012252012267708778,
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-0.04768314212560654,
0.01850803941488266,
0.04020672291517258,
0.015054869465529919,
0.008015620522201061,
0.02853642962872982,
0.057920344173908234,
-0.007685491815209389,
0.01... |
<p>I have set of 'n' numbers in an array. Is there a statistical distribution that would generate randomly picked 'n' numbers from the same array such that there are no duplication. </p>
<p>For example, if I have an array {1,2,3,4,5}, I should be able to generate 5! ways of combinations of the same numbers like
{5,4,3... | g62370 | [
0.007356811314821243,
0.01177956536412239,
0.011448649689555168,
-0.04623575881123543,
-0.02879338338971138,
-0.0376536026597023,
0.012688573449850082,
-0.022814204916357994,
-0.017439132556319237,
-0.045466382056474686,
-0.02678588405251503,
-0.015775548294186592,
0.040327832102775574,
0.... |
<p>Imagine a graph where the x-axis is time in minutes (continuous) from 0 to 360. And the y-axis represents 'z' values. Of this continuous time course graph, I have 8 time points w/ their corresponding real z-values. Here is the data frame 'real_df' with that real data.</p>
<p>real_df:</p>
<pre><code>timepoints ... | g62371 | [
0.0355304479598999,
-0.02707790397107601,
-0.014655767939984798,
-0.03497431054711342,
0.03583076596260071,
-0.07702252268791199,
0.04349857196211815,
0.0012213037116453052,
-0.044336918741464615,
0.009192308411002159,
-0.03603262081742287,
0.010216888971626759,
0.050881773233413696,
-0.00... |
<p>I am new to R and trying to practice with some exercises. Given a data set with 40 observations and 5 variables. Spending is the the response and there are 4 predictors. I started with a linear model Residuals:</p>
<pre><code> Min 1Q Median 3Q Max
-51.082 -11.320 -1.451 9.452 94.252
Coeffi... | g62372 | [
0.010787458159029484,
-0.10927098244428635,
-0.015312330797314644,
0.005507661495357752,
-0.045742183923721313,
0.00915086455643177,
0.05264616385102272,
0.00965940672904253,
-0.05667295679450035,
-0.011245214380323887,
-0.045459356158971786,
0.012540324591100216,
0.004419206641614437,
-0.... |
<p>In this <a href="http://en.wikipedia.org/wiki/CLs_upper_limits#Origin" rel="nofollow">wikipedia section</a>, the first block equation claims that</p>
<p>$P(n_b \leq n^* | s+b)=P(n\leq n^* | b)$</p>
<p>Some context (also found in that linked section): $n_b$ follows $Pois(b)$ and $n_s$ independently follows $Pois(s)... | g19412 | [
0.0042306347750127316,
0.05707918480038643,
-0.02469596266746521,
-0.0051580616272985935,
0.01752699352800846,
-0.01787865348160267,
0.012564176693558693,
0.051089294254779816,
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-0.022563068196177483,
-0.08402495831251144,
0.033779602497816086,
-0.004106959793716669,
... |
<p>Are neural networks using classification more robust / reliable than using regression to produce a single value? The only reason I would think so is that it would be easier for the network to adjust the weights to accommodate a fixed number of outputs as opposed to manipulating the weights in order to output any nu... | g62373 | [
0.03802528232336044,
-0.01681937649846077,
0.0005768040427938104,
-0.005459480453282595,
0.023870909586548805,
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0.046845149248838425,
0.03696322813630104,
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-0.016486862674355507,
0.019699832424521446,
0.004639320075511932,
0.08218136429786682,
0.01... |
<p>I have recently advised some colleagues on the malpractice of binning a continuous variable, which was used in order to put it as a covariate in a regression model and retained as a significant predictor. They responded that when summed responses to several Likert item are not normal (in this case extremely skewed) ... | g19414 | [
-0.0009257270721718669,
-0.03303598612546921,
-0.007241911254823208,
-0.07193528115749359,
-0.002593070501461625,
-0.022009793668985367,
0.03250795230269432,
0.03185361251235008,
-0.015325494110584259,
-0.007674320135265589,
0.06694802641868591,
0.05308384820818901,
0.04066023603081703,
-0... |
<p>Is it always better to have categorical predictor variables when performing a multinomial logistic regression analysis? or can it be done using continuous predictor variables? If a predictor variable should always be categorical, what is the reason behind it?</p> | g62374 | [
0.011398250237107277,
0.000683958875015378,
0.03077782690525055,
0.016515349969267845,
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0.027651168406009674,
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-0.01161073800176382,
0.019749820232391357,
-0.008311287499964237,
-0.00405966816470027,
0.... |
<p>I am working with a product that turns survey data into useful statistics. Reviewing their code, has made me somewhat nervous, and I'm not a statistician, so I hope I can ask for clarity of the following problem: </p>
<p>Out of a survey S, for a product P. Respondents where asked if they </p>
<ol>
<li>liked the pr... | g34432 | [
-0.0024021416902542114,
0.0020397447515279055,
-0.005081014707684517,
-0.054357826709747314,
0.053488995879888535,
-0.007824604399502277,
0.002707442967221141,
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-0.00844427291303873,
0.0023727586958557367,
0.03842439502477646,
0.038709260523319244,... |
<p>I am using a control chart to try to work on some infection data, and will raise an alert if the infection is considered "out of control".</p>
<p>Problems arrive when I come to a set of data where most of the time points have zero infection, with only a few occasions of one to two infections, but these already exce... | g41909 | [
0.017423134297132492,
0.004537888802587986,
-0.002193432068452239,
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0.011454281397163868,
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0.03589487448334694,
-0.059910789132118225,
0.0248036477714777,
0.006382993422448635,
0.0636439323425293,
-0.01... |
<p>A "seismic section" shows amplitude for m discrete x values along its horizontal axis times n discrete time values along its vertical axis:
<img src="http://i.stack.imgur.com/L6zwW.jpg" alt="Seismic section"></p>
<p>Peaks in amplitude (black) are centered on horizons; interfaces between different geological layers.... | g62375 | [
0.05646670237183571,
-0.03223290294408798,
-0.007063040975481272,
-0.03372994810342789,
0.020755846053361893,
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0.02800983004271984,
0.0075963507406413555,
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-0.02461831271648407,
0.01930883899331093,
0.01927562803030014,
0.030585208907723427,
0.0451... |
<p>I have a two level nested structure data and two weights: for the first and second level. I normalized each weight so that the sums of each weight is equal to the total sample size at the first level. Is this correct or should the second level weight only be equal to the level 2 sample size? </p> | g34434 | [
0.046835754066705704,
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0.009088089689612389,
0.0015860865823924541,
0.027349650859832764,
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0.04487497732043266,
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-0.03384200111031532,
0.00034510722616687417,
0.003781708423048258,
0.013881792314350605,
... |
<p>I found that $AR(1)$ process $x_t=\phi x_{t-1}+\epsilon_t$ is not always Gaussian given Gaussian innovations $\epsilon_t$. This only happens when the $AR(1)$ model coefficient is very large. This goes against with <a href="http://en.wikipedia.org/wiki/Autoregressive_model" rel="nofollow">the theory</a> (If the white... | g62376 | [
-0.026042623445391655,
-0.0071530453860759735,
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0.008774089626967907,
0.07015284150838852,
0.010207903571426868,
0.04834499582648277,
0.02846846729516983,
0.017594018951058388,
0.032643962651491165,
-0.02494967170059681,
0.06921543926000595,
0.08018774539232254,
0.028... |
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