question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I am looking for an appropriate method to analyse these data/situation: We sell electronic devices. Customers are encouraged to report defective devices. Around every months we calculate the cumulative rate of {defective_devices}/{all_sold_devices}. I would like to monitor for sharp increases in the rates of defecti... | g68409 | [
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<p>Suppose I'm given the mean and one quantile (e.g. the 20% quantile) of a random variable $x$, and I want to find the parameters $\alpha$ and $\beta$ of a Beta distribution that has the same mean and quantile. Is there an efficient way to do it? </p>
<p>Using just the mean, I know that since $\bar{x} = \frac{\alph... | g49445 | [
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<p>I am currently working with a logistic semi-parametric model in R using the mgcv package. The output from the model gives the standard log-odds coefficients; however, reviewers have requested marginal effects (like the ones in Stata using the margins command). I would like to do average marginal effects (though, m... | g40905 | [
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<p>I have built a beta regression model with log link for predicting adherence. My dependent variable's range is 0 to 1.When I used a test set to calculate the predicted values with the parameter estimates from this model, the values were out of range (>1 and max was 2.3).
Is it wrong if I scale them to 0 to 1 range? ... | g28427 | [
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<p>I am solving some regression problem with RandomForests in Matlab, using it's default TreeBagger class for this task. While I managed to get reasonable result already, there are few questions which I can't find answers by simple google search. All questions below are for regression task.</p>
<ol>
<li><p><code>predi... | g68410 | [
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<p>I am new to SEM and I am trying to run CFA for a 3-item Job satisfaction scale in Amos. I am getting the following as results.</p>
<pre><code>Chi-square = .000
Degrees of freedom = 0
Probability level cannot be computed
</code></pre>
<p>I am not able to understand what does this mean.
Please help me understand how... | g68411 | [
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<p>Apologies in advance for poor terminology / description below; I'm trying my best but I do not know the correct wording.</p>
<p>Let's say a "sample" is some fixed number $n$ of boolean values (I'll use 1=true, 0=false):</p>
<pre><code>1 0 0 0 1 0 0 1 1 1 1 1 0
</code></pre>
<p>Now I have a list of samples all of ... | g68412 | [
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<p>I am trying to estimate the kernel density for number of days a child is sick. Around 73% of children report not being sick, i.e. zero. How do I estimate a kernel density for this censored variable using Stata?</p> | g49805 | [
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<p>I have bootstrapped a linear model in PROC GLM. Now I want to construct CI's around the parameter estimates. For binary variables, it's straightforward: drop the reference category where the parameter estimates are zero. However, for each replicate, the interaction of the binary term and a quadratic term produces... | g68413 | [
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<p>I have two datasets from some Web store (like Amazon). Datasets have one and the same structure. Each record in these datasets has the following attributes:</p>
<pre><code>ID - user ID
ProductCnt - count of products user bought
DepartmentCnt - count of departments user was shopping
PayTotal - sum of payments made... | g28434 | [
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<p>Spam filtering is an example of classification task where machines achieve approximately similar accuracy as humans. On the other hand, <a href="http://research.microsoft.com/pubs/74609/CCS2007.pdf" rel="nofollow">Asirra</a> (recognizing cats and dogs in images) is an example where humans significantly outperform ma... | g68414 | [
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<p>I am working on decision making under uncertainty, in which I have four technologies which I should compare them in terms of some decision criteria. These decision criteria are evaluated as probability distribution functions from which I extract two values including modal value and confidence interval values for eac... | g68415 | [
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<p>Let's say I have a data set which looks like below and I'm running a linear model to predict income on two predictors.</p>
<pre><code>date date-1 income region age
mar apr 50 2 55
apr may 10 3 40
may jun 35 1 35
....
Income = B... | g68416 | [
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<p>We're trying to use a Gaussian process to model h(t) -- the hazard function -- for a very small initial population, and then fit that using the available data. While this gives us nice plots for credible sets for h(t) and so on, it unfortunately is also just pushing the inference problem from h(t) to the covariance... | g492 | [
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<p>I have been using various GARCH-based models to forecast volatility for various North American equities using historical daily data as inputs.</p>
<p>Asymmetric GARCH models are often cited as a modification of the basic GARCH model to account for the 'leverage effect' i.e. volatility tends to increase more after a... | g28439 | [
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<p>I have some <a href="http://en.wikipedia.org/wiki/Ordinal_scale#Ordinal_scale">ordinal data</a> gained from survey questions. In my case they are <a href="http://en.wikipedia.org/wiki/Likert_scale">Likert style</a> responses (Strongly Disagree-Disagree-Neutral-Agree-Strongly Agree). In my data they are coded as 1-... | g49471 | [
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<p>In GEE, if you increase the number of clusters would this increase or decrease the standard errors of the regression coefficients? Would the estimated std error of the regression coefficients be smaller or larger than the true std error of the coefficients?</p> | g31130 | [
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<p>I was asked this question. My initial conclusion is that there isn't enough information to calculate the probability. I would appreciate it if anyone could provide provide their insight.</p>
<p>Scenario:<br>
Department of Defense is looking to purchase a good. Department of Defense has determined that a fair price ... | g68417 | [
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<p>I am trying to best understand how to interpret the type 3 analysis of effects output from <code>proc logistic</code> in SAS. I understand it to be interpreted in the same way you would interpret a type 3 sum of squares in a linear regression. For example, I want to model gas price by season (winter,fall,summer,sp... | g68418 | [
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... |
<p>In Random forest algorithm, Breiman (author) constructs similarity matrix as follows:</p>
<ol>
<li><p>Send all learning examples down each tree in the forest</p></li>
<li><p>If two examples land in the same leaf increment corresponding element in similarity matrix by 1</p></li>
<li>Normalize the matrix with number ... | g68419 | [
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<p>The problem (not homework) I practiced is </p>
<p>Consider the probability space $([0,1], B_{[0,1]}, P)$ where $B_{[0,1]}$ is the Borel set and $P$ is Lebesgue measure on $[0,1]$. For any integer $n>0$, there exist $m$ and $k$ such that $n = 2^m-2+k$ and $0\leq k \leq 2^{m+1.}$ Define </p>
<p>$$X_n(\omega)=\lef... | g68420 | [
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<p>I am representing my 3d data in covariance matrix. I just want to know what the determinant of a covariance matrix gives. If the determinant is positive, zero, negative, high positive, high negative, what does it mean or represent?</p>
<p>Thanks</p>
<p>EDIT:</p>
<p>Covariance is being used to represent variance f... | g68421 | [
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<p>I've got some ordinal variables b and a and a categorized variable c. I would like to fit a multinomial logit regression from the library car.
I tried to ignore the ordinal scale.
I have the following data:</p>
<pre><code> a<-c( 3, 4, 4, 4, 3, 4, 3, 3, 4, 2, 2, 4, 3, 3, 3, 1, 3, 2, 2, 3, 3, 1, 3... | g68422 | [
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<p>I have two time series of daily returns on two stock indices (S&P 500 and BOVESPA)
that I would like to estimate the portfolio value at risk (VaR) for. Since these are
indices from two different regions they do not naturally line up smoothly as their
business days are unequal due to some country specific holid... | g68423 | [
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<p>I have some data. Does anybody know a function which can fit the parameters of a t-distribution of this data when I know the numbers of degrees of freedom?</p>
<p>Thanks!</p> | g68424 | [
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<p>I have six ratios (females-males). These are the observed values:</p>
<p>1.78 - 1.17 - 0.53 - 1 - 0.85 - 0.56</p>
<p>I need to run a chi-squared test to show that these ratios are significantly different.</p>
<p>I expect all these ratios to be equal. But as for the “equal” value, there is no expectation. It coul... | g28447 | [
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<p>Imagine that I have the following data:</p>
<pre><code>GroupA <- c(2,4,3,1,2,3,3,2,3,1)
GroupB <- c(3,5,4,2,4,3,5,5,3,2)
</code></pre>
<p>Then when I call in R</p>
<pre><code>wilcox.test(GroupA, GroupB)
</code></pre>
<p>and then</p>
<pre><code>wilcox.test(GroupB, GroupA)
</code></pre>
<p>I get different ... | g609 | [
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<p>I am comparing the Facebook posts of a TV news organization's Facebook Page to the contents of the TV news broadcast. (This is called "agenda setting" in communications research.) I have used a grounded theory approach to code hundreds of Facebook posts and segments of the TV show. </p>
<p>Here is the problem: Ther... | g68425 | [
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... |
<p>I need to use Breusch-Pagan to check heteroscedasticity of my timeseries.</p>
<p>I found the explanation of the function, here: <a href="http://hosho.ees.hokudai.ac.jp/~kubo/Rdoc/library/lmtest/html/bptest.html" rel="nofollow">http://hosho.ees.hokudai.ac.jp/~kubo/Rdoc/library/lmtest/html/bptest.html</a></p>
<p>Loo... | g28449 | [
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<p>Let us assume I have two data sets with <em>n</em> observations of data pairs of independent variable <em>x</em> and dependent variable <em>y</em> each. Let us further assume I want to generate a distribution of regression slopes for each data set by bootstrapping the observations (with replacement) <em>N</em> times... | g37438 | [
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<p>I am surveying the use of statistical significance testing (SST) to validate the results of cluster analysis. I have found several papers around this topic, such as</p>
<p>"Statistical Significance of Clustering for High-Dimension, Low–Sample Size Data"
Yufeng LIU, David Neil HAYES, Andrew NOBEL, and J. S. MARRON</p... | g68426 | [
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<p>Assume a noise comes from a specific point on a line, noise which I can detect but not completely accurately. My uncertainty is assumed to be Gaussian. </p>
<p>I want to gather evidence about the real location of the noise source from the noise I can perceive. So, I represent my accumulating knowledge with a Gaussi... | g538 | [
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<p>I am quite new to Machine Learning and come from a computing background.</p>
<ol>
<li><p>I have a quite big set of features (~50) with about 4k observations. Is it correct thinking to include all of them in a multiple linear regression model? Wouldn't that possibly introduce overfitting? If that's the case, is it s... | g68427 | [
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<p>I am trying to use the <code>mlogit</code> package in R and have been following the vignette trying to figure out how to get the marginal effects for my data.
The example provided uses continuous variables, but I am wondering how to do this with categorical explanatory variables.</p>
<p>I have a value of risk which... | g68428 | [
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<p>I want to fit mixed model using lme4, nlme, baysian regression package or any available. </p>
<p><em><strong>Mixed model in Asreml- R coding conventions</em></strong></p>
<p>before going into specifics, we might want to have details on asreml-R conventions, for those who are unfamiliar with ASREML codes.</p>
<pr... | g28453 | [
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<p>In Excel for a project I'm trying to model the density, distribution and survival function ($1-F(X)$) and I can't get the density to sum to one and I can't get the distribution to go to one. For the parameters I'm using $\alpha=3$ and $\theta=10$. I'm getting extremely strange results such that halfway through the d... | g68429 | [
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<p>Can we do <em>k</em>-means clustering on percentage data (like 56%, 44%, 22%, 13%, etc.)?<br>
There is a data set, and data in various parts are measured in percentages.</p> | g68430 | [
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<p>I have two pretty long binary vectors ($\sim 3$ mi positions), and I found the distance between then using Jaccard's Index $J=\frac{a}{a + b + c}$. After getting the result, I asked myself how much can I trust this value.</p>
<p>I thought about two alternatives, and would like to hear your advice to be sure that th... | g68431 | [
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<p>I have (matched) case-control data. The data is collected in batches in such a way that the batch determines some quality of the data (there is a 'batch' effect). </p>
<p>Also, the cases and controls were not randomly distributed among these batches. So batch 1 contains only cases, batch 2 contains only controls, b... | g68432 | [
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<p>I'm using logistic regression to predict the occurrence of tree carcasses falling after a mortality event. Data include a variety of topographic and tree characteristic variables and also time since death for many individuals over a number of sites. Data were taken repeatedly over several years. The way things were ... | g37435 | [
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<p>I am having a bit of confusion. I was reading this paper where it explained that bagging technique greatly reduces variance and only slightly increases bias. I didn't get it how come it reduces variance. I know what variance and bias is. Bias is the inability of the model to learn the data. Variance is something sim... | g68433 | [
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<p>I am fitting a logistic model to data using the glm function in R. I have attempted to specify interaction terms in two ways:</p>
<pre><code>fit1 <- glm(y ~ x*z, family = "binomial", data = myData)
fit2 <- glm(y ~ x/z, family = "binomial", data = myData)
</code></pre>
<p>I have 3 questions:</p>
<p>1) Wh... | g38370 | [
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<p>I have a couple question that have arisen studying Weighted Least Squares from <a href="http://rads.stackoverflow.com/amzn/click/0324660545" rel="nofollow">Woolridge</a>, all centering around corrections for heteroskedisticity in cross sectional data.</p>
<ol>
<li><p>Woolridge first shows an example of weighted lea... | g38371 | [
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... |
<p>I am trying to analyse the following table:</p>
<p>5 5 5 5 4 5 5 5 5 </p>
<p>3 4 3 3 4 4 3 5 5 </p>
<p>Each number is a success score out of 5 attempts, so we can assume binomial (p, 5), for unknown p. Each column pertains to one person. The bottom row contains the "pre" test results and the top r... | g68434 | [
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<p>I have a class assignment to implement a couple existing ways to extract feature vectors from a given set of texts, so they can be used to classify those texts using k-nearest neighbour algorithm. The texts are newspaper articles from Reuters, and they are to be sorted based on the country related to the story, and ... | g68435 | [
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<p>I have a regularized linear regression model with a large number of parameters (~100,000) that has been optimized using a sparse fitting algorithm (coordinate descent with early stopping). The model parameters and prediction accuracy were cross-validated using repeated random subsampling. I want to assess the stat... | g38372 | [
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<p>I am trying to classify a dataset which has 20 features and a class (target) feature. The problem is that "class-1" is found in 25% of cases while the rest 75% is "class-2" examples.</p>
<p>My question is : How can i under sample instances of class2 (or oversample class1 instances) in R?</p>
<p>I already tried to ... | g68436 | [
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<p>I have a data that I have used discriminant function analysis with. In the results, one variable has a standardized canonical function coefficient that is greater than 1.0. I didn't think these could be greater than 1 and I am not sure what to make of it. </p> | g28463 | [
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<p>I have a data base from a stratified multi-stage survey. Due to confidentiality reasons, they do not gave me the strata neither the psu, ssu… variables. Instead they gave me the:</p>
<ul>
<li>“Final weights” which sum is approximately equal to N. these weights include the deff, a non response weight and they are al... | g28464 | [
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<p>I have answered all of the following questions I need someone to verify me or if there is a better approach I would like to know about.</p>
<blockquote>
<p>Q1) Look at your model summary to find the x variable whose model coefficient is most significantly different from 0. (You don't have to write R code to find ... | g28465 | [
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<p>I want to test how well my data fit the particular power law:</p>
<p>$y=ax^b$</p>
<p>where $b$ , for physical reasons, should equal exactly $-0.5$. I would like to find the probability that the data do not obey this, or more correctly what the chance is of obtaining the data if it did equal $-0.5$.
Here's some typ... | g35951 | [
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<p>Suppose that $X$ ~ $Binomial(n,p)$ for $0 < p < 1$</p>
<p>Why does no unbiased estimator exist for $1/p$?</p>
<p>My approach:</p>
<p>We try to find the structure of $E_p(U(x))$, where $U(x)$ is any estimator of $1/p$.</p>
<p>Now, we will have:</p>
<p>$\sum{U(x)\binom{n}{x}p^x(1-p)^{n-x}}<\sum{U(x)\bino... | g831 | [
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<p>How can I show that the geometric mean $( \prod_{i=1}^{n} X_i )^{1/n}$ of a random sample of size $n$ from a distribution with pdf $f(x;\theta)=\theta x^{\theta-1},0<x<1,$, zero elsewhere, and $\theta>0$ is a sufficient statistic for $\theta$?</p>
<p>By the Factorization Theorem we can see that:</p>
<p>$... | g68437 | [
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<p>just wondering is there a symbolic matrix algebra software like Mathematica that would solve complicated matrix expressions?</p>
<p>Many thanks!</p> | g28467 | [
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<p>I am looking into contrasting two groups with regards to frequency differences over a few time points.</p>
<p>To make it clearer:
I have for group 1, the frequency difference 5; 4; 1; 2; 3
and for group 2: 3; -3; -1; -2; 2</p>
<p>The negative differences are crucially important as it essentially shows the 'typical... | g68438 | [
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... |
<p>I am told, in Gaussian Processes, adding covariance function noise to others, say SEiso or Materns, cause a better result, since it prevents from over fitting. I appreciate if someone could put more light on it !</p> | g68439 | [
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<p>I want to model counts as being dependent on two nominal variables, one continuous variable (all as fixed effects) with 3rd-order interactions and one grouping variable (as random effect). However, I have an overdispersion in outcomes (I used <code>lmer</code> function from <code>lme4</code> library). How should I m... | g68440 | [
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... |
<p>I'm performing the cox regression analysis, where I have the model with 1 time-independent (treatment (yes/no)) and 1 time-dependent predictor (blood pressure level). </p>
<p>Outcome is death (yes/no). Time until death is measured in days and the count starts after the date of treatment prescription (time=0 days) i... | g68441 | [
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... |
<p>I have posted a "similar" question in <a href="http://stats.stackexchange.com/questions/29611/how-to-interpret-the-output-of-survival-analysis">another thread</a>. But I think that question is not specific/concrete enough to get the answer I expected.</p>
<p>I know that, in survival analysis, the concordance index ... | g49896 | [
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<p>Given a dataset X with N observations in 11 dimensions, where each variable is restricted to be >= 0, how is it possible to fit an 11-dimensional log-normal distribution to this dataset?</p>
<p>I only found sources for fitting an univariate lognormal to data, but I didn't find anything for the multivariate case.</p... | g38382 | [
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<p>I have a 4-dimensional function $F(a,b,c,d)$ which I need to optimize (find the minimum) Each of the 4 parameters of my function $(a,b,c,d)$ are made to vary in steps over a range, so each one can take only a certain finite number of values:</p>
<p>$a:\{a_1,a_2, ...a_A\}\,;\, b:\{b_1,b_2, ...b_B\}\,;\, c:\{c_1,c_2,... | g28472 | [
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0.021693451330065727... |
<p>I have performed a 2x2 experiment to measure the effects of two genetic factors on the occurrence and size of a rare birth defect. When an individual has the defect, we can measure its size (size is a continuous value greater than zero, with no upper bound.)</p>
<p>Here is some size data similar to what we're seein... | g28473 | [
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0.025... |
<p>I have been playing around with post processing the results of the random forest for regression machine learning algorithm in order to try and do better than the default mean of all trees prediction. Chapter 16 of <a href="http://www-stat.stanford.edu/~tibs/ElemStatLearn/" rel="nofollow">Elements of statistical lear... | g68442 | [
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0.05198809504508972,
0.003... |
<p>I've attended a course on Machine Learning and another one in Network Analysis, and I wonder if this two topics already intersect, in particular I'm interested in the following model:</p>
<ul>
<li>we have a mobile network (that is, the nodes perform a random walk in some area, then sending a message within some ass... | g28475 | [
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0.05506434291601181,
... |
<p>Is there a substitute for measuring precision, recall of a classifier (binary or multi-class) to evaluate its performance using information-theoretic quantities like entropy, mutual information or normalized mutual information?</p> | g35954 | [
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<p>I'm using the <code>URCA</code> package in <code>R</code> to test for cointegration by Johansen's method. <strong>Can anyone tell me what the weights (loading matrix) tells me or what I would use it for?</strong> I understand what the critical value, test statistic and eigenvectors are for but confused by the loadin... | g68443 | [
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-0.0... |
<p>I was trying to derive the equations from page 109 in "elements of statistical learning" (image below)
<img src="http://i.stack.imgur.com/qkaZi.png" alt="enter image description here"></p>
<p>To be honest, I am not sure how the covariance $\Sigma$ is estimated (the third bullet point in image). Can someone kindly s... | g68444 | [
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0.0... |
<p>I've already read all the pages in this site trying to find the answer to my problem but no one seems to be the right one form me...</p>
<p>First I explain you the kind of data I'm working with...</p>
<p>Let's say that I have an array vector with several names of city, one for each of 300 users. I also have anothe... | g68445 | [
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0.0... |
<p>In <a href="https://class.coursera.org/ml-003/lecture" rel="nofollow">Andrew Ng's Machine Learning Coursera Class</a>, he covers anomaly detection in multiple dimensions for both independent univariate Gaussians and multivariate Gaussians, the latter being more costly than the former.</p>
<p>Would running independe... | g68446 | [
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0.0... |
<p><strong>Experiment Design:</strong></p>
<p><strong>Process</strong>: Outputs the order in which to do the work (assumption: ordering of work items is most preferred/valuable by stakeholders)</p>
<p><strong>Work items</strong>: The process above produces a rank ordering of items. Individual teams select work items ... | g68447 | [
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0.017287449911236763,
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0.0059568132273852825,... |
<p>I have a dataset of project case studies for a new type of research method for Government agencies to support decision making activities. My task is to develop an estimation method based on past experience for future projects for estimation purposes.</p>
<p>My dataset is limited to 50 cases. I have 30+ (potential... | g68448 | [
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0.0... |
<p>Can anyone tell me the difference between using <code>aov()</code> and <code>lme()</code> for analyzing longitudinal data and how to interpret results from these two methods?</p>
<p>Below, I analyze the same dataset using <code>aov()</code> and <code>lme()</code> and got 2 different results. With <code>aov()</code>... | g68449 | [
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<p>I have something strange going on. My phi coefficient of two binary variables is .07 while my odds ratio of the same two binary variables is 1.80. How is this possible?</p> | g68450 | [
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<p>Basically, I have two distributions with the same mean value and same number of observations.</p>
<p>One distribution is experimental data, the other being pre-generated.</p>
<p>I need to be able to determine the probability these two distributions are of the same set, in order to determine if statistical signific... | g28485 | [
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<p>Let's say I test how variable <code>Y</code> depends on variable <code>X</code> under different experimental conditions and obtain the following graph:</p>
<p><img src="http://i.stack.imgur.com/hpihy.png" alt="enter image description here"></p>
<p>The dash lines in the graph above represent linear regression for e... | g68451 | [
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0... |
<p>I'm trying to figure out how to reproduce in Python some work that I've done in SAS. <a href="https://gist.github.com/ccheaton/8393329" rel="nofollow">Using this dataset</a>, where multicollinearity is a problem, I would like to perform principal component analysis in Python. I've looked at scikit-learn and statsmod... | g68452 | [
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-0.01215590... |
<p>I was wondering if anyone could help me with information about Kurtosis (i.e. is there any way to transform your data to reduce it?)</p>
<p>I have a questionnaire dataset with a large number of cases and variables. For a few of my variables, the data shows pretty high kurtosis values (i.e. a leptokurtic distributio... | g68453 | [
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0.0015721645904704928,
0.06337128579616547,
-0.0... |
<p>I have data that is equivalent to:</p>
<pre><code>shopper_1 = ['beer', 'eggs', 'water',...]
shopper_2 = ['diapers', 'beer',...]
...
</code></pre>
<p>I would like to do some analysis on this data set to get a correlation matrix that would have an implication similar to: if you bought x, you are likely to buy y.</p>... | g28486 | [
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0.07865676283836365,
-... |
<p>I start with a presumably non-stationary time series. By some criterium $k$ I extract $n_k$ pairs of times $(t_{k,i,2},t_{k,i,1})$.
Now I compute the following quantity: $\bar{\tau} = \frac{1}{K} \sum_k \frac{1}{n_k} \sum_i (t_{k,i,2}-t_{k,i,1})$
What I'm looking for is the error of that quantity. I first began by s... | g68454 | [
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0.029840951785445213,
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<p>Here is the dual problem for L2 support vector machine:
$$\max_{\alpha\in\mathbb{R}^{n}} 2\alpha^{T}y-\alpha^{T}\left(K+n\lambda Id_{\mathbb{R}^{n}}\right)\alpha$$
$$\forall i\in\left\{ 1,\ldots,n\right\} ,\,\alpha_{i}y_{i} \geq0$$</p>
<p>However, using the Lagrangian formulation, I get the following. Is there an a... | g68455 | [
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0.03560523688793182... |
<p>I am investigating through logistic regression models the effect of different kinds of genetic variation (in a set of 27 genes), and of the number of genes hit by such variation, on a disease. At first, I built a model predicting the <em>Status</em> of individuals (Disease/Healthy) on the basis of the presence/absen... | g68456 | [
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0.0478... |
<p>I'm trying to normalize a set of columns of data in an excel spreadsheet.</p>
<p>I need to get the values so that the highest value in a column is = 1 and lowest is = to 0, so I've come up with the formula:</p>
<p><code>=(A1-MIN(A1:A30))/(MAX(A1:A30)-MIN(A1:A30))</code></p>
<p>This seems to work fine, but when I ... | g68457 | [
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<p>I'm trying to determine the influence (direction and relative strength) of certain attributes of incoming students to an academic program on their successful completion of the program. My sample size is in the range of several hundred students. There are about 20 variables all together, all of which we could reasona... | g38413 | [
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<p>Can someone refer me to a good reference that explains the connection between Bayesian statistics and generative modeling techniques? Why do we usually use generative models with Bayesian techniques?</p>
<p>Why it is especially appealing to use Bayesian statistics in the absence of complete data, if at all?</p>
<p... | g38414 | [
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<p>I recently came across this identity:</p>
<p>$$E \left[ E \left(y|x,z \right) |x \right] =E \left(y | x \right)$$</p>
<p>I am of course familiar with the simpler version of that rule, namely that $E \left[ E \left(y|x \right) \right]=E \left(y\right) $ but I was not able to find justification for its generalizatio... | g28491 | [
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<p>I have a problem with the estimation parameter for Zipf. My situation is the following: </p>
<p>I have a sample set (measured from an experiment that generates calls that should follow a Zipf distribution). I have to demonstrate that this generator really generates calls with zipf distribution.
I already read this... | g68458 | [
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0.0046088737435638905,
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<p>I see sometimes written (see below for examples) that given a random sample from less than 10% of the population then it's reasonable to assume that the data is independent. I wonder why 10% and not another percentage.</p>
<p>Examples:</p>
<ol>
<li><p><a href="http://www.openintro.org/stat/textbook.php" rel="nofol... | g28495 | [
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0.012927372008562088,
0.017417246475815773,
0.04088336229324341,
0.020226934924721718,
-0.034549299627542496,
0.017683936282992363,
0.014616614207625389,
0.00024440104607492685,
... |
<p>I want to statistically compare the mean values from eight different groups. I do not have the raw data, but have the sample size, mean and associated standard deviation and standard error. I was wondering if there was any code in R to do the ANOVA test on summary data, as well as the subsequent post-hoc, pair-wis... | g28496 | [
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0.004225988406687975,
-0.0063423337414860725,
0.021939726546406746,
-0.01586148701608181... |
<p>I am trying to design a model that can estimate the number of customers I will receive in every store every month using the number of customers I received every month in every store for the last five years up to and including the day before's numbers. How can I even approach this from a programming perspective? What... | g68459 | [
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0.04238047078251839,
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0.020484382286667824,
... |
<p>I'm trying to solve the problem below:</p>
<p>Let $X_1,...,X_n$ be independent with PDF $f(x)=e^{-x}$ if $x>0$ and zero otherwise and define
$$X_{(n)} = \mathrm{max}\{X_1,..,X_n\}$$</p>
<ol>
<li><p>Find the CDF of $X_{(n)}$.</p></li>
<li><p>Find a sequence of numbers $a_n$ so that the sequence of random
variabl... | g68460 | [
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0.0009385372395627201,
0.0083282720297575,
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-0.015179328620433807,
0.03632998839020729,
0... |
<p>I'm interested in finding some way for doing "stochastic linearisation by irregular waves of ship roll motion equation". I found some publications about it</p>
<p><img src="http://i.stack.imgur.com/dpYR3.png" alt="OTC14324"></p>
<p>but its hard for me to understand, how to do this iteration - exactly to what itera... | g68461 | [
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<p>I am analyzing my data of my experiment and I have a question concerning the repeated measures ANOVA. I have 2 independent variables (temperature and salinity), 1 dependent which is length and 2 measuring points (3rd and 7th day) of the experiment. </p>
<p>So my question is, can I use repeated measures ANOVA when I... | g28502 | [
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-0.027162926271557808,
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0.003690794575959444,
-0.02326965145766735,
-0.032346971333026886,
-0.03693275526165962,
0.016780449077486992,
-0.04354295879602432,
0.033653512597084045,
-0.052799634635448456... |
<p>If there are 2 nlme models with same non-linear mean function, model 1 and model 2, how do you compare them ? Which R function does this for us ?</p>
<p>And when there are random effects or fixed effects, I don't know how a nested model is defined ? </p>
<p>For example model 1, </p>
<pre><code>`model1 <- nlme... | g28503 | [
-0.004355001728981733,
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0.012174774892628193,
0.024429859593510628,
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-0.029776670038700104,
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0.0285797119140625,
0.05496468022465706,
... |
<p>I have a joint probability density function f(x,y) numerically in R. X is the probability males get a disease; Y the probability females get the disease. I want to extract from this bivariate data the univariate density for the odds ratio. That is I have a some function T(X,Y) and need the density function of T. In ... | g68462 | [
0.014502176083624363,
0.01892019249498844,
0.00996700581163168,
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0.05649371072649956,
-0.018896576017141342,
0.0262177512049675,
-0.03... |
<p>I am new to this site, so my apologies if I am not asking the question the right way for this site. I am actually trying to understand Latent Class Analysis & Latent Transition Analysis. I have read a few articles. I found ProcLTA and ProcLCA in SAS, but in R I could only find poLCA package, and nothing for LTA.... | g68463 | [
-0.0003331825428176671,
-0.09856679290533066,
0.018929410725831985,
-0.04956614598631859,
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0.02525126002728939,
0.04974726215004921,
-0... |
<p>I have been informed that I should have a p value listed in my EFA results section?
I am confused by this and wonder what am I missing?</p> | g68464 | [
0.019850589334964752,
-0.01421904657036066,
0.010094217024743557,
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0.0646146684885025,
0.0270173791795969,
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-0.073468416929245,
-0.0023213685490190983,
-0.007015747483819723,
0.013971260748803616,
0.000... |
<p>I am performing regression with ARIMA model because of autocorrelation of my data. My data are the concentration of air in the workplace and gathered by real time monitor with interval of 1 minute. I would like to get the value of intercept and coefficient of variable working or not.</p>
<p>I used to use R to perfo... | g68465 | [
0.019520731642842293,
-0.07055720686912537,
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0.02181830257177353,
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0.01999494805932045,
-0.040... |
<p>I've upto one million transaction dataset in the <strong>Oracle database</strong> & it's a data warehouse based system. I need to prepare a <strong>ATM card fraud</strong> detection model based on the dataset available. Is it possible to do in real time?</p>
<p>I would really appreciate if some links for <stron... | g68466 | [
0.012432851828634739,
0.04070661962032318,
0.004463175777345896,
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0.047966085374355316,
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0.029505247250199318,
0.05420935899019241,
-0.012... |
<p>What are other feature representations for documents that are used for clustering textual documents? The only representation I'm aware of is tf-idf. Are there other ones?</p> | g68467 | [
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0.047415222972631454,
0.0... |
<p>I have a number of distributions which I want to fit to a CDF that is comprised of one or more Gaussian CDFs. I was able to use weighted least squares regression to find the best fit parameters for each regression depending on the number of modes I give the model (e.g. each Gaussian CDF has three parameters, mu, sig... | g68468 | [
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-0.05379753187298775,
-0.061758853495121,
0.09133360534906387,
0.0232... |
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