question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I have an unknown data set consisting of 1024 vectors (integers with <code>1024 rows</code>, <code>30 columns</code>). What is the <code>maximum</code> number of neurons (<code>x_dimension * y_dimension = number_of_neurons</code>) for a 2-dimensional Kohonen Self Organizing Map for this dataset (without having any k... | g17975 | [
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<p>I use e1071 package for naive bayes classification. My dataset is having 2 condition/feature (FF1 and FF2) to predict a class of signal (ELO or FP). When I used the following line of code:</p>
<pre><code>A_classifier <- naiveBayes(A_train[,c(1:2)], A_train$Label)
</code></pre>
<p>it works fine and the condition... | g68241 | [
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<p>I am trying to do confirmatory factor analysis on data that is coded binary (<code>0</code> no, <code>1</code> yes). UCLA suggests using a tetrachoric correlation matrix, which,
however, assumes that binary variables reflect underlying continuous variables. Is there a way to relax this assumption and use logistic pr... | g68242 | [
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<p>I'm just starting to look into exponential smoothing models. Is there a way to fit a linear regression with exponentially-smoothed errors, similar to the standard technique of fitting a regression with ARMA errors? Or is this generally considered a bad idea?</p>
<p>Of course, I can come up with heuristics, like fit... | g49021 | [
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<p>I have a data set that behaves approx. Standard normal. It is an image where each observation is a pixel intensity. I want to cluster this into three different sets by fitting a 3-gaussian mixture model. I want one cluster to be "significantly" smaller than the mean (0) one to be around the mean and one "significant... | g28165 | [
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<p>In some literature, I have read that a regression with multiple explanatory variables, if in different units, needed to be standardized. (Standardizing consists in subtracting the mean and dividing by the standard deviation.) In which other cases do I need to standardize my data? Are there cases in which I should... | g49325 | [
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<p>How do I interpret hierarchical regression results?</p> | g28167 | [
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<p>I'm writing an MCMC algorithm in R and I'm wondering about the following: say we have two parameters, $\theta_1$ and $\theta_2$. I want to update each one at a time from the corresponding posterior conditional distributions. Say $\theta_1^{(0)}$ and $\theta_2^{(0)}$ are the initial values. Then at iteration 1 I upda... | g68243 | [
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<p>I am trying to find a statistical test for comparing the ratios of occurrences and would appreciate any help.</p>
<p>There are two groups; treatment and control.
Each group has three categories of outcomes; High, medium and low blood pressure.
The number of subjects is 100 for each group.</p>
<p>Now, let's say, fo... | g28170 | [
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<p>I am trying to estimate the following unobserved components model using the MARSS package </p>
<p>$y_t = \mu_t + \varepsilon_t $</p>
<p>$\mu_t = \mu_{t-1} + \beta_{t-1}$</p>
<p>$\beta_t = \beta_{t-1} + \zeta_{t}$</p>
<p>with a restriction on the variance of the errors: $\sigma^2_{\zeta} = \frac{1}{\lambda}\sigma... | g68244 | [
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<blockquote>
<p>Let $\mathbb P(X=1) = \mathbb P(X=-1) = 1/2$. Define </p>
<p>$$X_n = \begin {cases} X & \text{with probability } 1- \frac{1}{n}\\
e^n & \text{with probability } \frac{1}{n} \end {cases}$$</p>
<p>Does $X_n \leadsto X$ (i.e., converge in distribution)? Does $X_n \stackrel{P}{\right... | g49664 | [
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<p>My question is how to tell if two regressions explain the data better than one. </p>
<p>Let me be more concrete with an example (which I'm making up as I go, it's not meant to be plausible). Say I'm interested in the relationship between income and happiness. Then I ask a lot of people about their income and happin... | g68245 | [
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<p>How do I interpret this predictive model?</p>
<blockquote>
<p>S&P500 Next Week = Earnings Per Share * 0.25 + Dividends Per Share *
-1.519 + Current S&P500* 1.018 + 5.409</p>
</blockquote> | g68246 | [
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<p><strong>Context</strong></p>
<p>In <a href="http://en.wikipedia.org/wiki/Transportation_forecasting" rel="nofollow">transportation planning</a>, agent-based <a href="http://www.microsimulation.org/IMA/What%20is%20microsimulation.htm" rel="nofollow">microsimulation</a> is a method to deal with the complexity of the ... | g37934 | [
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<p>I am reading about <a href="http://en.wikipedia.org/wiki/Stochastic_dominance" rel="nofollow">stochastic dominance in wikipedia</a>. I don't comprehend the meaning of "equal in distribution".</p>
<p>$x_B \overset {d}{=} (x_A+y)$</p>
<p><strong>What does $\overset {d}{=}$ mean?</strong> </p>
<p>I understand that e... | g68247 | [
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<p>I am having problems with defining the error terms for a two way repeated measures ANOVA in R. My data consists of wood density estimates for three radial positions (inner, middle, and outer) along a core extracted from a tree. There are a total of 20 tree species, 6 individuals of each species, and two cores from e... | g68248 | [
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<p>I have income based on zipcode from US census data, I think they also provide income based on gender for whole of US, income based on age for whole of US, and income based on zip code. Now I need to find out what the income of a person from a certain zipcode, of a certain age and gender. What model should I use? How... | g37715 | [
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<p>I'm working as a liaison between a researcher and a stats team at a university. I'm a database admin who is working on using business intelligence tools to offer the option of (as of right now) offer CART analyses in .PDF form over the internet. I'm using Microsoft Business Intelligence Development Studio to do th... | g28183 | [
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<p>Assume I have a data set as follows:</p>
<pre><code>Total_Cost Average_Cost Quantity
12 6 2
21 7 3
28 7 4
30 6 5
36 6 6
</code></pre>
<p>The linear relationship between Total_Cost and Quan... | g68249 | [
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<p>I'm trying to forecast a seasonal time series based on its historical values, and also two more time series (that are seasonal themselves.) </p>
<p>I'm trying to use an <strong>auto.arima</strong>, and I'm going to input the other two time series (the exogeneous regressors) as a contatenated list of dummy variable... | g68250 | [
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<p>I came a cross some survey results that show user preferences, asked in the form of the most and least preferred choices. The result reported was something like "x % of people chose option A as their most preferred" and "y % of people chose option B as their least preferred". It seems to me that there is some depend... | g46273 | [
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<p>Why is the sum of squares error function of noisy input and noisy target variables very similar to the error function for only noisy input?</p>
<p>This is the relevant part in <a href="http://research.microsoft.com/en-us/um/people/cmbishop/prml/" rel="nofollow">Bishop</a>'s book: </p>
<blockquote>
<p>Another vie... | g68251 | [
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<p>I'm not involved in drug testing, but it is my understanding that most trials are performed using a control and a treatment group (or perhaps a few discrete treatment groups). This data is then used to determine effectiveness of a drug, and hopefully uncover any deleterious side-effects before the drug is released o... | g68252 | [
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<p>I'm using machine learning to do text classification right now, I first use a training data to train my classifier, then use this classifier to classify text document into different classes. With the time goes on, some new words will arise
and I need to adjust my training vocabulary to correctly classify these docum... | g49047 | [
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<p>Being quite new to the field, it occurs to me that there are multiple and fundamentally different ways of assessing the quality of a logistic regression:</p>
<ul>
<li>One can evaluate it by looking at the confusion matrix and count the misclassifications (when using some probability value as the cutoff) or
<br></... | g47904 | [
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<p>One of the parameterization of the negative binomial distribution is NB($m,r$), $$\Pr(X = k) = \left(\frac{r}{r+m}\right)^r \frac{\Gamma(r+k)}{k! \, \Gamma(r)} \left(\frac{m}{r+m}\right)^k \quad\text{for }k = 0, 1, 2, \dots.
$$ I would like to consider the parameterization NB($m$, $\phi$) where $\phi=1+\frac{m}{r}$.... | g68253 | [
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<p>I am sorry for having to ask a simple probability question, but I have been thinking about it for weeks and an extensive google search has given no answers.</p>
<p>I have a group of 628 questions. 31 Questions belong to category A. 150 participants will each be given 50 randomly sampled questions from the total 628... | g28195 | [
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<p>I have a dataset covering small and large companies. The three dummy variables are "large manufacturing", "large service", and "large governmental" companies. Roughly 90% of the firms can be classified by these categories (the remaining firms are small and are not classified in manufacturing, service, and government... | g28196 | [
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<p>I realize that this is contrary to "standard" multiple imputation using Rubin's rules, but I have a data set were a variable with a lot of missing values is most likely MNAR. It represents a large portion of the data (40%), so I would like to fill it in, but doing so using the mi command in Stata rests on faulty ass... | g68254 | [
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<p>I have a bunch of datasets (gene expression profiles). <br> From the datasets, I am gonna analyze co-expression profiles using WGCNA (<a href="http://labs.genetics.ucla.edu/horvath/CoexpressionNetwork/Rpackages/WGCNA/Tutorials/" rel="nofollow">http://labs.genetics.ucla.edu/horvath/CoexpressionNetwork/Rpackages/WGCNA... | g28198 | [
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<p>I am variable selecting for a time-series forecasting model that has parameters sampled from a high variance sampling distribution centred near zero and that undergo changes over time. Each predictor has a tiny but non-zero correlation (in population terms) with the response. Lasso et al. are problematic here since ... | g28201 | [
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-0.0016273529035970569,
0.0013424112694337964,
0.048069488257169724,
0.00... |
<p>Let $X_{1},...,X_{n}$be distinct observations (no ties). Let $X_{1}^{*},...,X_{n}^{*}$denote
a bootstrap sample (a sample from the empirical CDF) and let $\bar{X}_{n}^{*}=\frac{1}{n}\sum_{i=1}^{n}X_{i}^{*}$.
Find $E(\bar{X}_{n}^{*})$ and $\mathrm{Var}(\bar{X}_{n}^{*})$.</p>
<p>What I have so far is that $X_{i}^{*}$... | g68255 | [
-0.05733379349112511,
0.02532416768372059,
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0.011021236889064312,
0.05740005895495415,
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0.0... |
<p>I am working on a data mining projects and I have to design following model.</p>
<p>I have given 4 feature x1, x2, x3 and x4 and four function defined on these</p>
<p>feature such that each function depend upon some subset of available feature.</p>
<p>e.g.</p>
<p>F1(x1, x2) =x1^2+2x2^2</p>
<p>F2(x2, x3) =2x2^2+... | g68256 | [
-0.028753865510225296,
-0.0022400517482310534,
0.012772767804563046,
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0.011712567880749702,
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-0.04169461131095886,
-0.05797155573964119,
0.030631624162197113,
0.06720666587352753,
... |
<p>I am trying to use DLM to model a time series. Candiate model includes local level, local trend and local trend with seasonal part. I do not know how to do model selection. Can AIC be calculated? I found no function in the R package <a href="http://cran.r-project.org/web/packages/dlm/index.html" rel="nofollow"><code... | g28202 | [
-0.006303295958787203,
-0.007050238084048033,
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0.0038229937199503183,
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0.05503023415803909,
0.10164300352334976,
... |
<p>Actually this question may be simple for you, but I need to learn the correct answer.<br>
If I remove misclassified instances from data set with Naive Bayes (it gives minimum FP rate) and then train logistic classifier on this filtered data set, will it overfit or not?</p>
<p>Thanks in advance.</p> | g68257 | [
0.03997701406478882,
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0.03678107261657715,
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-... |
<p>I have a dataset consisting of around 200 individuals, whose outcome is either of state $0$ or $1$. I am able to make binary classifiers and predictors on this set and build ROC-curves for them just fine, but now I'm interested in a problem which has me kind of stumped.</p>
<p>Suppose I have some even larger popula... | g28204 | [
-0.025858769193291664,
0.00887127872556448,
0.020950857549905777,
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0.01599252037703991,
0.0026153388898819685,
0.010757791809737682,
0.0602615624666214,
-0.... |
<p>I have a variable with some missing values</p>
<pre><code>a <- rnorm(100);
a[sample(1:100,10)] <- NA;
a;
</code></pre>
<p>How can I fill missing values with previous non missing value?</p>
<p>for example if I have sequence:</p>
<p>a<- (3, 2, 1, 6, 3, NA, 23, 23, NA);</p>
<p>first NA should be replaced ... | g18143 | [
0.030207987874746323,
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0.002294856822118163,
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0.01593371108174324,
0.0036064970772713423,
0.00864010863006115,
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0.015316221863031387,
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0.015392436645925045,
0.013074292801320553,
0.046... |
<p>I have a completely within-subjects design with 3 independent variables:</p>
<ul>
<li>Trial type (3 levels)</li>
<li>Task order (2 levels)</li>
<li>Modality (3 levels)</li>
</ul>
<p>However, for one of my levels of Trial type, the Task order and Modality levels are redundant (because it is essentially a baseline m... | g28207 | [
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0.050732046365737915,
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... |
<p>Say, $\psi | Y, {Y}^{*}, {\sigma}^{2}$~$N(\mu, {\Lambda}^{-1})$ this is a bivariate normal </p>
<p>Does the ${\Lambda}^{-1}$ actually mean precision or variance. I was told in some Bayesian papers, the second parameter actually means precision. I didn't think so, but maybe someone else has read more paper would... | g49064 | [
0.02591869793832302,
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<p>This is a very basic question, so please bear with me.</p>
<p>I've been learning about AB Testing, which is largely used in internet marketing to examine the effectiveness of certain aspects of ads, websites, etc.
Here's a couple links to people who want to know more about AB Testing:</p>
<p><a href="http://visual... | g68258 | [
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0.032922081649303436,
0.06369969248771667,
0.010201294906437397,
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-0.0248... |
<p>I have a data set with sales as $Y$ and total retail shelf space ($x$). </p>
<p>I want to investigate the diminishing return, i.e. whether additional shelf space would contribute to more sales. I did regression or Arima model where I found that the squared shelf space ($x^2$) was significant. Thus there is a dimini... | g47984 | [
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-0.001... |
<p>I am using singular vector decomposition on a matrix and obtaining the U, S and Vt matrices. At this point, I am trying to choose a threshold for the number of dimensions to retain. I was suggested to look at a scree plot but am wondering how to go about plotting it in numpy. Currently, I am doing the following usin... | g18152 | [
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0.005792798008769751,
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-... |
<p>I am trying to test importance sampling for a simple a Wiener process $W_t$ in R:</p>
<pre><code>set.seed(123)
Z <- matrix(rnorm(12*1000),12,1000)
W <- apply(Z,2,cumsum) #Wiener process simulated 1000 times for 12 periods
B <- W-(1:12) #Brownian motion with drift -1
w <- exp(-W[12,]) #Radon-Nikodym deri... | g28213 | [
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0.02824784629046917,
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0... |
<p>my stats question is as follows:</p>
<p>The research group I work for have developed a theoretical growth model for a particular species of fish. The idea is that if you provide some initial starting values for the model you then generate an expected growth curve along with 95% confidence bands. To extend the model... | g49066 | [
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<p>I am using <code>randomForest</code> to generate a model, and at the end I don't know how I can get the final coefficients that the model is fitting. I know that for linear regression, you just type <code>summary(lm)</code> where <code>lm</code> is your model, and you get the coefficients.</p> | g68259 | [
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0.000... |
<p>I want to cluster my data first using k-means and then determine a regression model for each cluster.
Then I want to evaluate the performance of this approach using split validation.
I can think of two alternative approaches for that:</p>
<p>a) clustering the complete data set and then splitting each cluster into a... | g28216 | [
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0.011830738745629787,
0.03358407691121101... |
<p>I am working on an imbalanced classification problem (about 90 thousand records total, of which 2% are target = Y and remaining are target = N). </p>
<p>My dataset has been prepared in SAS Enterprise Guide and has a mixture of binary flags (coded as 0 or 1) and interval/numeric variables. I want to implement SMOTE ... | g68260 | [
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0.015226355753839016,
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0... |
<p>I've read that it's bad to do this, but am looking for details as to why.</p>
<p>Suppose we're trying to fit the linear model $Y_i = \beta_0 + \beta_1 X_{1i} + \beta_2 X_{2i} + \epsilon_i$ where $Y$ is continuous and $X$s are categorical with many levels. We don't have any opinion on how the levels should be groupe... | g28217 | [
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0.01398447621613741,
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0.0896... |
<p>In Gaussian Processes, SVMs, kernels are used (as to my understanding) as similarity measure. However, they have the constraint that any kernel has to be represented as a dot product. i.e. $k(x_1,x_2)=\langle f(x_1), f(x_2)\rangle$. Note that $f(x)$ could map x to a higher dimension e.g. $f(x)=[x^2\,\,\,\, \sqrt{2}x... | g68261 | [
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0.0244267750531435,
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0.... |
<p>I am stuck with one query on mlogit.
I have three options (0,1,2) for prediction of probabilities.
The model equation is: </p>
<pre><code>Model1 = mlogit(A ~ 1 | B + C + D, data = XYZ, reflevel = "0")
Predicted = predict(Model1, newdata = XYZ, probability = TRUE)
</code></pre>
<p>Or </p>
<pre><code>Model2 = ml... | g28218 | [
0.027438035234808922,
-0.04238024353981018,
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0.034797802567481995,
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-0.030305610969662666,
0.05085594207048416,
0.019283616915345192,
0.06535772234201431... |
<p>I work with habitat use data (summarized binomial data: visited / did not visit) which I fitted with a mixed model of the binomial family with a random factor accounting for repeated sampling of the same individual. I simply want basic descriptions of the data - effects of sex and year on the proportion of time spen... | g68262 | [
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0.02079756185412407,
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0.... |
<p>Let's say I have taken a sample $S$ of a population. I am trying to figure out the population mean.</p>
<p>Because I have only made one sample, the best I can do is assume that $\bar S$ is the mean of the population. I can't get a confidence interval for the population mean, because I can't calculate the standard d... | g28219 | [
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0.0046007996425032616,
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-... |
<p>I am working with spoken language data and use linear models do determine the relationship between different phonological processes in my data. </p>
<p><strong>Background</strong> </p>
<p>Measures of the regularity of syllable durations are influenced by how <em>syllable</em> is defined. I used two methods to dete... | g68263 | [
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0.010169455781579018,
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0.011789784766733646,
0.0034511182457208633,
0.0426... |
<p>Recently I ran into a test using both zipf's and self-similar generated datasets. I followed the description from Jim Gray's paper on generating such datasets (<a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&ved=0CEIQFjAB&url=http://research.microsoft.... | g48051 | [
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0.04827718064188957,
0.03180834650993347,
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-0.043022118508815765,
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0.03810602426528931,
0.04525848478078842,
0.01760... |
<p>I have a 2 level repeated measures DV of accuracy, and a covariate of response bias. As response bias increases, accuracy level 1 increases while level 2 decreases. I want to see if there is a difference in the means of the groups after controlling for response bias. </p>
<p>I can't do it with an ANCOVA. Can I ju... | g28221 | [
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0.050446756184101105,
0.03784222900867462,
0.0... |
<p>I have read elsewhere that one's choice of hidden layer activation function in a NN should be based on one's <em>need</em>, i.e. if you need values in the range -1 to 1 use tanh and use sigmoid for the range 0 to 1.</p>
<p>My question is how does one know what one's <em>need</em> is? Is it based on the range of the... | g68264 | [
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0.004354632925242186,
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0.0041097188368439674,
0.04869342967867851,
0... |
<p>Say I have a model $y=f_n(x_1,x_2,x_3)$. </p>
<p>Here say $y$ is categorical and binomial response. i.e. $y$ can be only 0 or 1. Data shows 87% 1 and 13% 0 values.</p>
<p>I fit a multinomial logit on a test dataset to try to predict $y$. Validation against a validation dataset showed 70% success. (Success meaning ... | g68265 | [
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0.07169635593891144,
... |
<p>I am comparing length of stay after laparoscopic and open appendectomy in over 160000 patients. LOS is typically a skewed variable so I use the median and interquartile range and ranksum test to describe the result, which is 2, IQR 2-3 and 2, IQR 2-4, p<0.0001. So there is a highly significant difference but it d... | g49077 | [
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0.016527259722352028,
0.039423707872629166,
0.028342686593532562,
0.027264755219221115,
... |
<p>In a simple linear regression model with two independent variables, if there is a strong correlation found between the variables, it is suggested that we should include only one of them in the model.</p>
<p>I am building a model where the dependent variable is <em>Lunch Cost</em> and the independent variables are <... | g68266 | [
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0.0248... |
<p>Here is my situation, I just got a list of 100 p-values, some of which are associated.</p>
<p>For details, these 100 pvalues could be seperated into 7 groups, each group was calculated from a expression dataset. However, these datasets had 10%~60% overlap among each other, that is the pvalues inside a dataset were ... | g49079 | [
0.038528237491846085,
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0.00008995264215627685,
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0.04787423461675644,
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0.04363786056637764,
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0.006830521859228611,
0.012168941088020802,
0.0... |
<p>Let $W = X_1/X_2$ where $X_1$ and $X_2$ are normally distributed with means $\mu_1,\mu_2$, variances $\sigma_{1}^{2}, \sigma_{2}^{2}$ and correlation coefficient $\rho$. The exact distribution of $W$ and the standard approximation assuming $X_2 > 0$ is wanted. </p>
<p>Why is studying the distribution of $W$ the ... | g68267 | [
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-0.008106016553938389,
0.00806862860918045,
-0.020292824134230614,
0.03822065144777298,
-0.03635232150554657,
-0.011357546783983707,
-0.01107916422188282,
0.0024617083836346865,
0.03809843957424164,
-0.004463333170861006,
0... |
<p>When doing analysis of growth trajectories you often find natural outliers. Often these are not because of any "errors" in the dataset, they are simply there because certain cases grew at an explosive rate compared to the majority of the cases in the dataset. A case in point is open source repositories where most se... | g68268 | [
0.008899610489606857,
0.023585960268974304,
0.00955137051641941,
0.027463221922516823,
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0.017277108505368233,
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0.037745606154203415,
0.0... |
<p>We have a variable, $X$, measured at pre-study and post-study and are studying the effects of $X$ across changes of several outcome variables (post-pre).</p>
<p>Currently we are using regression models to investigate the change in $X$ (post-pre) effect while including pre-study $X$ to control for the initial level ... | g68269 | [
-0.05143643915653229,
-0.03900562599301338,
0.012751725502312183,
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0.024579275399446487,
0.03188958019018173,
... |
<p>I have the following questions:</p>
<p>Suppose we have the following chart, which represents the relationship between faculties and types of objects; for example CTE represents Computer Technologies, and the intersection between CTE and Wood says that at the CTE faculty there are 56 types of wood. </p>
<p>My qu... | g41775 | [
0.03584500774741173,
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0.015132366679608822,
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0.013573306612670422,
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0.0791640356183052,
0.036318402737379074,
0.05292524769902229,
-0.04001... |
<p>I am trying to approximate a product of expectations:</p>
<p>$\operatorname{E}[f(x)]\operatorname{E}[g(x)]=\sum_x P(x) f(x) \sum_x P(x) g(x)$</p>
<p>with $N$ Monte Carlo samples $(x_1,x_2,...,x_N)$ from $P(x)$:</p>
<p>$\operatorname{E}[f(x)]\operatorname{E}[g(x)] \approx \left( \frac{1}{N} \sum_i f(x_i) \right) \... | g68270 | [
-0.02974548563361168,
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0.021622708067297935,
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0.07575039565563202,
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0.... |
<p>I am running a multiple regression of Y~a+b+c+d etc... </p>
<p>I want to do a quick check to see whether my different explanatory variables are colinear (they're a mix of categorical and continuous). There seems to be a whelm of complicated statistics behind all this -- would looking at the R-squared value of a s... | g39223 | [
0.011802857741713524,
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0.04112715646624565,
0.06... |
<p>I am currently working with the national forest inventory of Mexico. A sample sceheme that collected data concerning the state of forests on points spread out all over the country. One of these variables is a cualitative one concerning ground damage/degradation due to many causes. E.g. pasture activities. This varia... | g28230 | [
0.01763029955327511,
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0.0012030178913846612,
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0.010226113721728325,
0.05132889747619629,
0.0... |
<p>A question about a shuffled vs. unshuffled correlation matrix</p>
<p>I took the correlation matrix and shuffled between its values symmetrically. (shuffled only the left lower triangle of the matrix and copied the values to the upper right triangle. saving the diagonal of ones untouched)
The eigenvalues spectrum of... | g68271 | [
-0.01546291820704937,
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-0.019970031455159187,
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0.017551342025399208,
0.05... |
<p>I have a list of 6,500 or so medical treatments, of which I have classified 700 or so as involving a physician or not. I am interested in both the specific question of how to calculate whether 700 observations is sufficient, and the general question about how one does power calculations in text mining.</p>
<p>A ty... | g49089 | [
0.019058706238865852,
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0.023420121520757675,
0.026457812637090683,
0.04656851291656494,
0... |
<blockquote>
<p><strong>Possible Duplicate:</strong><br>
<a href="http://stats.stackexchange.com/questions/22439/incremental-or-online-or-single-pass-or-data-stream-clustering-refers-to-the-sam">Incremental or Online or Single pass or Data Stream Clustering refers to the same thing?</a> </p>
</blockquote>
<ol>
... | g49797 | [
0.07147034257650375,
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0.02277993969619274,
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0.0467451848089695,
0.0818437710404396,
0.01... |
<p>I received the following message in SAS:</p>
<blockquote>
<p>Measures of association between the observed and predicted values were not calculated
because the mean scored predicted probabilities are indistinguishable when they are
classified into intervals of length 0.008.</p>
</blockquote> | g28233 | [
0.03666267916560173,
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0.04449184983968735,
0.... |
<p>Suppose we seek to approximate an arbitrary distribution $p_1(x)$ by a normal
$p_2(x) \sim \mathcal N(\mu, \Sigma)$. How can I show that the values that lead to the smallest Kullback–Leibler
divergence are:
$$
\mu_1 = \mathbb E_1[X]
$$
and
$$
\Sigma_1 = \mathbb E_1[(X − \mu)(X − \mu)^T],
$$
where the notat... | g68272 | [
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0.05581818148493767,
0.0666... |
<p>I don't have SAS and the dataset with me, so I made up this table (from my memory). Basically this is what I got:</p>
<p><img src="http://i.stack.imgur.com/oqaet.jpg" alt="enter image description here"></p>
<p>After deciding to leave the variable $age$ and $risk$ in my model, I created this interaction term. Accor... | g49798 | [
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0.017939075827598572,
0.029155828058719635,
0.0... |
<p>Maybe this is a dumb question as my experience has been more on statistical computing algorithms than on data analysis. But I would like to know, or have references on, analysis process most of statistical data analysts go through for each data analysis project. </p>
<p>If I make a "list", to complete data analysi... | g49091 | [
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0.0059505063109099865,
0.08319070190191269... |
<p>Can you suggest any quick and simple clustering analyses, for univariate real-valued data? In other words, I have $n$ real numbers, $x_1,\dots,x_n$ where $x_i \in \mathbb{R}^+$, and I want to cluster them. I don't know a priori the best number of clusters, so that's something the method would need to discover as w... | g68273 | [
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0.035916347056627274,
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0.013480359688401222,
0.017706971615552902,
0.09031561762094498,
... |
<p>I am reading a manuscript that provides the "maximum posterior probability" in a Bayesian context as a statistical summary of a parameter.</p>
<p>Is the term "maximum posterior probability" equivalent to (i.e., "exchangeable" with) "posterior mode"?</p> | g18284 | [
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0.07408014684915543,
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0.04610294848680496,
-0... |
<p>If I have 10 Variables (Q,W,E,R,T,Y,U,I,P,A) and I want Q to be my response variable and other 9 to be my predictors variable. Do I write it in R like this </p>
<p><code>EXAMPLE<-glm(Q~W+E+R+T+Y+U+I+P+A,family=binomial)</code></p>
<p>Furthermore, what if Q is Binary (goes from 1 to 0) and all the other 9 vari... | g68274 | [
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0.023518605157732964,
0.022141505032777786,
0.... |
<p>I am working with two sets of data and would like to determine if they come from the same distribution -- hence the two population KS-test. At this point, I have binned both sets of data, counting the number of entries in each bin, to create relative frequency histograms. These binned arrays look like:</p>
<pre><c... | g18296 | [
0.0444757454097271,
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0.011165632866322994,
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0.025302955880761147,
0.06127900257706642,
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-0.011662015691399574,
0.014934922568500042,
0.05025194585323334,
0.03657817840576172,
0.0... |
<p>I have six dependent variables (count data) and several independent variables, I see that in a MMR the script goes like this:</p>
<pre><code>my.model <- lm(cbind(DV1,DV2,DV3,DV4,DV5,DV6) ~ IV1 + IV2 + ... + IVn)
</code></pre>
<p>But, since my data are counts, I want to use a generalized linear model and I tried... | g49413 | [
0.01668073609471321,
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0.04438251629471779,
0.02061227709054947,
0.003... |
<p>I'd like to know how to best structure categorical variables.</p>
<p>Based on some reading I did, most researchers suggest making the categorical variable into a factor.</p>
<p>Let's say my categorical variables are something like </p>
<pre><code>Variable ( no ordering here, 9999 is just missing)
1
2
3
-1
9999
A... | g28241 | [
0.039105817675590515,
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0.015448075719177723,
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0.03835466131567955,
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-0.02959410846233368,
0.027886221185326576,
0.01174198742955923,
0.00899880938231945,
0.010... |
<p><strong>Preamble</strong>: I've had a couple of statistics courses @ uni, but can't really say I got "hooked" (I read NNT's Black Swan <em>before</em> starting the degree :), hence the depth of my statistical knowledge remained (so far) rather shallow and mechanical, lacking deeper insight and a "feeling" for the ma... | g28242 | [
0.012579371221363544,
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-0.06420273333787918,
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0.03127747401595116,
0.05272471159696579,
-0.... |
<p>The following is a problem from <em>Bayesian Data Analysis 2nd ed</em>, p. 97. Andrew Gelman has not included its solution in the guide on his website and it has been driving me crazy all day. Literally all day.</p>
<p>For some data $y$, modeled as a binomial distribution with population $N$ and probability $\theta... | g68275 | [
0.04008914530277252,
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0.004729780368506908,
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0.012573412619531155,
0.018854549154639244,
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0.009406909346580505,
-0.010064953938126564,
0.01041558850556612,
-0.026131097227334976,
-0... |
<p>I am trying to analyse data collected through the Self-Assessment Manikin (SAM), which uses three pictorial scales to assess the three dimensions of <em>pleasure</em>, <em>arousal</em> and <em>dominance</em>. Participants are explicitly instructed that they can tick either of the five pictures or <em>any of the four... | g68276 | [
0.002547777257859707,
0.07118885964155197,
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0.011786920949816704,
0.05483531951904297,
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-0.020322000607848167,
0.034052710980176926,
-0.037629805505275726,
0.053571175783872604,
... |
<p>Suppose someone is trying to estimate the diagnostic prevalence of ADHD in a cohort of individuals born in 1985. What type of study is this? This is not a prospective cohort study because we are not comparing two groups (i.e an exposed and unexposed group). All individuals in this study are exposed (born in 1985).</... | g68277 | [
0.04736558720469475,
0.012991591356694698,
0.00527430372312665,
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0.02056756056845188,
0.020147087052464485,
0.03287622332572937,
0.044561319053173065,
-0.031497370451688766,
0.03610939905047417,
0.044176485389471054,
0.018647368997335434,
0.041694... |
<p>If you have two groups lets say Y any Z that change over "time", how do you compare if the increase rate of x and y over time is same or not. How would i set this up in R</p> | g48161 | [
0.003069804748520255,
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0.00007913276203908026,
0.024857787415385246,
0.0379750058054924,
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0.04144028201699257,
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0.02175493724644184,
0.028059452772140503,
0.04434685409069061,
-0.026739437133073807,
0.06... |
<p>I have some results where the tester claims the following values:<br/>
Sensitivity: 0.525, Specificity: 0.925, Precision: 0.516, Accuracy: 0.907</p>
<p>Where<br/>
Sensitivity=TP/(TP+FN), <br/>
Specificity=TN/(TN+FP), <br/>
Precision=TP/(TP+FP), <br/>
Accuracy=(TP+TN)/(TP+TN+FP+FN)</p>
<p>I'm having trouble see... | g68278 | [
-0.0008549909107387066,
-0.02425065077841282,
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0.021580910310149193,
0.019671356305480003,
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-0.01643742248415947,
-0.011799869127571583,
0.034211184829473495,
0.05863858386874199,
... |
<p>I'm curious about how to understand the accuracy of my model which I computed with <code>glm( family = binomial(logit) )</code>.</p>
<p>In some articles it is mentioned that we should perform chisq test with residual deviance with it's DoF.
When I call summary() of my glm module.
<strong>"Residual deviance: 9109.9... | g28251 | [
0.007251686416566372,
-0.03254878148436546,
0.0120655233040452,
0.03325200825929642,
0.054390884935855865,
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0.06343790888786316,
0.026012420654296875,
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-0.020848575979471207,
-0.031469717621803284,
0.03608972206711769,
0.05586319789290428,
-0.0252... |
<p>I need to obtain the functional (i.e.: statistic obtained from the empirical distribution function) associated to the <a href="http://en.wikipedia.org/wiki/Uniformly_most_powerful_test" rel="nofollow">most powerful test</a> to contrast $H_0: f_o$ vs. $H_1: f_1$, using a sample of size $n$.</p>
<p>In particular, my... | g68279 | [
-0.00765492208302021,
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-0.017688702791929245,
-0.03832071274518967,
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0.042200807482004166,
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0.011809307150542736,
-0.01969568245112896,
0.06201736256480217,
... |
<p>I've read through the many excellent discussions on the site regarding interpretation of confidence intervals and prediction intervals, but one concept is still a bit puzzling:</p>
<p>Consider the OLS framework and we've obtained the fitted model $\hat y = X\hat\beta$. We're given a $x^*$ and asked to predict its r... | g68280 | [
0.014514879323542118,
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0.02574426308274269,
0.02409602515399456,
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-0.056027673184871674,
0.006892280653119087,
0.0127309150993824,
0.0413309708237648,
-0.0... |
<p>Suppose a random variable $X$ has probability density function $f_0$ and $f_1$ under null and alternative hypothesis, respectively.</p>
<p>Is it possible to find another random variable, $g(X)$, which has the same density under null & alternative hypotheses?</p>
<p>Thanks in advance!</p>
<p>P.S. Not consider... | g37161 | [
0.026403440162539482,
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0.032656729221343994,
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0.055460598319768906,
... |
<p>I have hourly values from which I extract every data over a threshold (Peak-over-threshold method). I then filter those extreme values so that i only get one value in a given 48 hours period. This leads to a Generalized Pareto (GP) distribution. I estimated the GP parameters with the standard Matlab built-in functio... | g68281 | [
-0.014105567708611488,
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0.054234061390161514,
-0.03355114907026291,
0.013771270401775837,
0.00693858228623867,
... |
<p>Bland-Altman plot measure the agreement between two different methods which measures the same variable. As far as I understand Bland-Altman can measure only if the two methods have the same unit of measurement. I want to measure the agreement between two methods which measure the same variable (a continuous variable... | g68282 | [
0.012898319400846958,
-0.05322142690420151,
0.011188924312591553,
-0.04796302318572998,
0.033263761550188065,
0.004781183321028948,
-0.01943124830722809,
-0.019897572696208954,
-0.031885940581560135,
-0.020001914352178574,
0.01500218827277422,
0.05796986445784569,
-0.028302935883402824,
0.... |
<p>I am using the metafor package in R. I have fit a random effects model with a continuous predictor as follows </p>
<pre><code>SIZE=rma(yi=Ds,sei=SE,data=VPPOOLed,mods=~SIZE)
</code></pre>
<p>Which yields the output:</p>
<pre><code>R^2 (amount of heterogeneity accounted for): 63.62%
Test of Moderators (... | g28263 | [
0.00544397858902812,
-0.03523755073547363,
-0.008841446600854397,
-0.03168685361742973,
0.007944321259856224,
0.02112066186964512,
0.03266468644142151,
0.0006417261902242899,
-0.016414955258369446,
-0.024170512333512306,
-0.005163532216101885,
0.028368910774588585,
0.04529657959938049,
0.0... |
<p>I need to cite the pdf(density) or cdf(distribution function) of a non-central scaled Student's t distribution. </p>
<p>There is an article about the non-central Student's t distribution <a href="http://en.wikipedia.org/wiki/Noncentral_t-distribution" rel="nofollow">http://en.wikipedia.org/wiki/Noncentral_t-distrib... | g68283 | [
0.012810468673706055,
0.002037427620962262,
-0.02177414670586586,
-0.10695377737283707,
-0.003939067013561726,
0.0062812091782689095,
-0.031674329191446304,
0.013262755237519741,
-0.04814167693257332,
0.029798200353980064,
0.010851041413843632,
-0.03322653844952583,
0.08845309168100357,
-0... |
<p>Suppose we have the following logistic regression model:</p>
<p>$$\text{logit}(p) = \beta_0+\beta_{1}x_{1} + \beta_{2}x_{2}$$</p>
<p>Is $\beta_0$ the odds of the event when $x_1 = 0$ and $x_2=0$? In other words, it is the odds of the event when $x_1$ and $x_2$ are at the lowest levels (even if this is not 0)? For ... | g15281 | [
0.0211423821747303,
0.0007133781327866018,
0.003468797542154789,
0.01508303638547659,
0.06186772882938385,
-0.0009092444670386612,
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-0.07442835718393326,
-0.03376496955752373,
0.044044096022844315,
-0.021924039348959923,
-0.0... |
<p>I have this question :the number of gun-related deaths per 100,000 people in 1994 was 14.24 in the United States, 4.31 in Canada, 2.65 in Australia, 1.24 in Germany, and 0.41 in England and Wales. Use the relative risk to compare the United States with the other countries. Interpret. I am not sure if I need to compa... | g68284 | [
0.06634678691625595,
-0.013291683979332447,
0.0004716712865047157,
-0.011109326034784317,
0.032609764486551285,
0.024928241968154907,
0.004731547087430954,
-0.013106250204145908,
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-0.00039578269934281707,
0.007440389599651098,
0.008735050447285175,
0.05447472631931305,
... |
<p>I am looking for publicly accessible data sets to explore some wisdom of the crowd ideas. </p>
<p>An ideal data set would contain predictions from a number of individuals (who were not collaborating with each other, or at least only minimally) on events with known outcomes.</p>
<p>Predictions in terms of probabili... | g28266 | [
0.005239296238869429,
0.04187163710594177,
-0.005250556860119104,
-0.03149626776576042,
0.006365916226059198,
0.010883644223213196,
-0.00756595516577363,
-0.015332894399762154,
-0.016765328124165535,
-0.06653448194265366,
0.059127338230609894,
-0.03656459599733353,
0.04851307347416878,
-0.... |
<p>Newbie, so please bear with me.. I'm trying to get my head around how I can use the awesome tool I found and what it does not give me any info about.</p>
<p>The case:
Using this site: <a href="http://hedwig.mgh.harvard.edu/sample_size/js/js_parallel_quant.html" rel="nofollow">http://hedwig.mgh.harvard.edu/sample_s... | g68285 | [
0.04105193167924881,
-0.021682491526007652,
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-0.051424697041511536,
0.009101035073399544,
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-0.0011385050602257252,
0.015471421182155609,
-0.062153734266757965,
-0.024397071450948715,
0.048991262912750244,
0.035377707332372665,
0.08280200511217117,
... |
<p>I have 6 sets of interval data each of which between 0 and 1. Each set, calculated by a computer program, is related to the degree of similarity between some sounds (pairwise).
What do you think in the best inter-rater reliability measure I can use to see how close the 6 judges are?
If I want to explain the data in ... | g49134 | [
-0.005862758494913578,
-0.018458351492881775,
-0.007067404687404633,
-0.06118354946374893,
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-0.051761385053396225,
0.010570261627435684,
0.0556042306125164,
-0.013980939984321594,
0... |
<p>I have some survey response data that are inconsistent and I'm not sure what is the best way to handle them. This is the nature of the inconsistency: </p>
<ol>
<li>Have you ever had a food poisoning episode that you think might have been caused by the food in a particular restaurant ? a) Yes b) No</li>
<li>Did any... | g28268 | [
0.037135396152734756,
-0.02418171614408493,
0.018337685614824295,
0.020752130076289177,
0.03323671221733093,
-0.009233950637280941,
-0.039074353873729706,
0.04220658540725708,
0.037039585411548615,
-0.04574640467762947,
0.035422902554273605,
0.009364129044115543,
0.007819807156920433,
0.04... |
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