question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>I am just learning R, and am aware that the package <a href="http://cran.r-project.org/web/packages/e1071/index.html" rel="nofollow">e1071</a> has a <code>naiveBayes</code> method that takes in predictor and class membership, and estimates the class prior using the relative frequency (ML estimate). </p>
<p>I would ... | g897 | [
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<p>I'm looking at this paper, </p>
<p><a href="http://www.stanford.edu/~hastie/Papers/AdditiveLogisticRegression/alr.pdf" rel="nofollow">http://www.stanford.edu/~hastie/Papers/AdditiveLogisticRegression/alr.pdf</a></p>
<p>around pages 10-11 (marked 346,347 in the pdf). This notation is introduced
$$
E_w[g(x,y)|x] := ... | g64749 | [
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<p>PCA performs a linear transformation on a data set to obtain a new data set, this time with eigenvector basis and eigenvalue loadings. If Z is our data set, P our linear transformation, and Y our new data set with eigenvector basis, the transformation is:</p>
<p>P*Z = Y .</p>
<p>but, quiet often Z is not our origi... | g64750 | [
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<p>I am using an ARIMA model to create a model for correlated errors from my regression model. I am using the <code>auto.arima</code> function from the <a href="http://cran.r-project.org/web/packages/forecast/index.html" rel="nofollow">forecast</a> package in R. I am able to get more data at some frequent interval afte... | g64751 | [
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<p>I have a probability question (if it is too basic, my apologies since I am learning), I can not get my head around.</p>
<p>Suppose I concatenate the sentences from many books and shuffle the sentences (so we do not know the book that a sentence is from) to have a "sentence database". We assume there is no duplicate... | g64752 | [
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<p>I am implementing robust regression on some data and when i tested the accuracy on a hold set of data, the accuracy was very bad. I have about 500 000 observations for the regression model and i deleted about 20% of the observations in such a way that each observation should include at least 3 of the 10 independent ... | g23043 | [
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<p>I need to implement a Metropolis Hastings where the acceptance probability $\alpha$ is not a probability but a logarithm of a score. The logarithm of a score is a negative float. </p>
<p>In original algorithm i have:</p>
<pre><code>alpha = compute acceptance probability with proposal distribution
Compute r = min(... | g64753 | [
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<p>Are there R some packages for analysis of alpha-lattice (0,1) designed experiment? My experiment includes two factors with two levels. The tests are performed in two replications with twenty blocks. Every block consists of 10 plots. </p> | g64754 | [
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<p>This is a very basic question - If two stocks have the same beta over same time period, does it mean they are 100% correlated over that time period?</p>
<p>Beta, in a CAPM framework is defined as Cov (R1, M) * Var (M). Where R1 is the return vector of a security 1 and M is the market return vector. Equating two bet... | g64755 | [
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<p>Suppose I fit a generalized mixed logistic model such like that:</p>
<pre><code>set.seed(2014)
require(lme4)
df<-data.frame(id=rep(1:5, c(8,10,12,14,15)),
out=c(rbinom(8,1,0.1), rbinom(10,1,0.3),rbinom(12,1,0.1),rbinom(14,1,0.05),rbinom(15,1,0.1)),
age=rnorm(59,50,10),
... | g64756 | [
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<p>I'm used to HLM 7 software and now I'd like to switch to Stata, for multilevel modelling (xtmixed).</p>
<p>To give an example imagine I have students(level1) nested within schools (level2).
In HLM I can easily add a second level variable (for instance schools beauty) choosing the equation of a coefficient (or inter... | g23055 | [
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<p>Out of curiosity, I want to understand how to model this problem. I've been hearing people suggest the use of linear regression but <strong>I am not sure how to encode this problem</strong> (included my attempt below) in R as I am a complete beginner in this area. </p>
<p>I have a task that can be done any number o... | g64757 | [
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<p>It's known that the paired t-test is equivalent to the random intercept model in the sense that the data for paired t-test is actually two repeated measures on the same subject and we can use a indicator variable as a covariate in the r.e. model stands for the two measures and with the random intercept to explain th... | g64758 | [
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<p>I have heard of survival analysis and life data analysis, but don't quite get the big picture.</p>
<p>I was wondering what topics they are covering? </p>
<p>Is it pure statistics, or just application of statistics on some specific area?</p>
<p>Is life date analysis part of survival analysis? </p>
<p>Thanks and r... | g64759 | [
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<p>I had a related question answered here:</p>
<p><a href="http://stats.stackexchange.com/questions/114190/rule-of-thumb-for-minimum-length-of-time-series-for-ar1-estimation">Rule of Thumb for minimum length of time series for AR(1) estimation</a></p>
<p>However the answer gives rise to a new question. I want to be a... | g23058 | [
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<p>I want to apply k-medoids algorithm using an incomplete distance matrix as input. How can I handle the lack of information of this matrix? Just ignoring the missing distances? Or is there a better way?</p> | g64760 | [
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<blockquote>
<p>Statistic (Linear normal model): $X_{hi} \sim N(\alpha_h+ \beta t_{hi}, \sigma^2)$. How to calculate $C_{95}(\beta)$ and $t$-test for $\beta = 2.5$?</p>
</blockquote>
<p>I am in the statistical model $X_{hi} \sim N(\alpha_h + \beta t_{hi}, \sigma^2)$ $h=1,..,3, i=1,..,n_h$ (Linear normal model) wher... | g64761 | [
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<p>I need help calculating the Mid-P of the confidence limits for the standardized mortality ratio, or any observed/expected ratio. I am familiar with the Mid-P for a binomial calculation but I am trying to understand how to calculate confidence intervals for a standardized mortality ratio under a Poisson distribution.... | g64762 | [
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<p>I have a spatio-temporal data set with (n,m) spatial and k temporal dimensions.</p>
<p>My initial analysis consisted of spatially averaging the data and looking at the time dependent behavior. This resulted in a vector of length k for the mean and standard deviations.</p>
<p>Now I want to average the those means, ... | g64763 | [
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<p>Working on dissertation. Theory: in K-12 education putting more administrative authority in the state board of education is "better" that leaving it to the local boards.</p>
<p>DV: data from 43 states on % kids graduating high school within 4 years.</p>
<p>IVs: I have 37 different measures for the types of adminis... | g64764 | [
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<p>Is there anything inherently wrong with trying to estimate the entropy of a multidimensional random variable by first transforming it (by some method) into a single-dimensional variable?</p> | g20628 | [
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<p>I have three sets of data (1 set before treatment, second during treatment and the third after), each of which consists of hundreds of trials on a specific task that involves choosing 1 from 7 possible choices, the answer for which may be correct or not (binary categorization). I'd like to determine whether the prop... | g23062 | [
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<p>I have a training dataset with (x1,x2,x3,y) and these contain some missing observations. I ran proc logistic on this training data and got the parameter estimates (bo, b1, b2, b3). </p>
<p>I tried to apply these estimates(bo, b1, b2, b3) on the test dataset which does not contain any missing observation using <stro... | g23063 | [
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<p>I am trying to use a naive Bayes classification technique to predict fraudsters (<code>Caller</code>). My training set of 138 instances has 5 columns viz. <code>Morning</code>, <code>Afternoon</code>, <code>Evening</code>, <code>Night</code> and <code>Caller</code>. <code>Morning</code> has 8 names; the rest all hav... | g64765 | [
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<p>I'm writing a research paper in entomology that compares 6 categorical variables (species) in terms of one dependent anatomic continuous variable. My samples look very normal by box-plots, etc. Looking at the "largest standard deviation can't be more than twice the smallest standard deviation rule of thumb, one of... | g64766 | [
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<p>I'm following a very good <a href="http://nbviewer.ipython.org/github/fonnesbeck/Bios366/blob/master/notebooks/Section4_2-MCMC.ipynb" rel="nofollow">IPython notebook</a> (the whole list can be found <a href="http://nbviewer.ipython.org/github/fonnesbeck/Bios366/tree/master/notebooks/" rel="nofollow">here</a>) in whi... | g23065 | [
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<p>Say I have the following college enrollment data:</p>
<p><strong>California</strong> </p>
<p>In 1975, 188,234 men and 156,612 women were enrolled in California colleges.<br>
In 2005, 194,416 men and 201,334 women were enrolled in California colleges. </p>
<p><strong>Texas</strong> </p>
<p>In 1975, 132,261 men an... | g64767 | [
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<p>Suppose I have two multivariate normal distributions. I have computed the KL divergence ($d_{LK}(N_1, N_2)$). Is there a way to measure a relative divergence between these two distributions?</p>
<p>For instance in a deterministic case, there is absolute error and relative error.
Let's say if KL divergence is analog... | g35024 | [
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<p>I developed an index value (vulnerability score scale of 0 to 1) using a series of variables. I would like to regress these variables with the index value to determine the relative predictive power of each variable. Can I do this? </p>
<p>I ran the regression and came up with standardized B coefficients. I then int... | g64768 | [
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<p>If X and Y are standardized variables and are perfectly positively correlated with respect to each other, how can i prove that $E[(X-Y)^2] = 0$?</p> | g23068 | [
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<p>I'm working with a dataset for which I only have means, standard deviations, and sample sizes for different levels of a continuous predictor.</p>
<p>E.G.</p>
<pre>
Y X SD_Y N_Y
5 1 3 4
10 2 6 2
15 3 2 8
</pre>
<p>I would like to determine the regression line that fits this data. I'm wracking my bra... | g64769 | [
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... |
<p>How do you show that the point of averages (x,y) lies on the estimated regression line?</p> | g64770 | [
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<p>I am learning adaptive filters and testing the performance of using Least Squares and Kalman filter for parameter estimation for $y = X + \text{noise}$. The model is autoregressive AR(2) model
$$y(t) = ay_{t-1} + by_{t-2}$$
and a Moving Average MA(2) model. I have obtained the parameters $(\hat{a},\hat{b})$ for AR ... | g9625 | [
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<p>can everyone tell me how to use ggplot2 make recursive partitioning survival tree?</p>
<p>I know " party " package can make a plot in R, however the plot is not looking good, and all the plots in the rest of my report are made by ggplot2.</p>
<p>for my plot, I printsreen and added labels manually. if there is a wa... | g64771 | [
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<p>I couldn't find a single MOOCs on Applied behavioral economics and statistics, on how can we used statistical analysis in behavioral economics. If someone can point me in the right direction, it would be great</p> | g64772 | [
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<p>I have fitted a zero-inflated beta regression model to my data in R, using the gamlss package. </p>
<p>However, I am unsure of how to assess the fit of the model to my data, i.e. finding a coefficient of determination. </p>
<p>Does anyone know if this can be easily calculated from a zero-inflated beta regression m... | g64773 | [
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<p>please help a sociologist struggling to get to grips with R and statistics in general..!</p>
<p>I've got a data set with 11 variables. I need to investigate the possible relationships between one of the variables (percentage of smokers in a population) and the rest of them- things like unemployment rate, education ... | g64774 | [
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<p>I am trying to identify habitat types from 85 plots. I intend to do a cluster analysis to identify habitat types, and hope to fit additional plots into the identified clusters. </p>
<p>(For context, I took measures from habitat plots in several different habitat types across a study site, then also measured the sam... | g10683 | [
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<p>I am developing a regression tree model I have an output variable with a very large standard deviation, I am wondering if I need to scale/normalize this output variable as metrics such as RMSE and R^2 my be quite sensitive to such deviations.</p>
<p>I understand that the input variables do not need to be scaled, my... | g64775 | [
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<p>I was recommended on StackOverflow to ask this question here: for me it's dataviz question, but perhaps it's more algorithmic in nature.</p>
<p>I have an ordered set of points in 2D, and would like to join them using some sort of spline to form a closed loop that does not intersect itself. This is, in fact, a singl... | g23075 | [
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<p>Lets say I am interested in finding the correlation of the following two metrics. They are aggregations and include the same input A in their formula.</p>
<p>Is it possible to talk about correlation of these metrics? With a satisfactory r-squared value, is it possible to use metric#1 as predictor of metric#2? Shoul... | g23076 | [
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<p>I am reading a research paper and the author tried to test the hypothesis: The service quality-behavioral intentions relationship has a different slope below and above the zone of tolerance relative to within it.</p>
<p>The equation and results of the regression analysis are:
<img src="http://i.stack.imgur.com/sgf... | g64776 | [
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<p>Is there anything nice I can say about the sum of two independent generalized Laplace variables, with different scales and sizes? i.e. are they distributed same as another generalized Laplace variable with some function of the moments, etc.</p>
<p>Edit: the PDF of generalized {Laplace or Gaussian} is: $f(x) = C\exp... | g64777 | [
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... |
<p>In an regression analysis it is sometimes valuable to introduce power terms as predictor variables. Age is a good example in the social sciences.</p>
<p>I know there is an general debate about introducing standardized predictors but here is my question:</p>
<p>If I want to introduce age as an standardized predicto... | g64778 | [
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<p>I am struggling with the choice of which test would be appropriate for my data. </p>
<p>My sample size is very small (n=16), thus I have chosen to perform a non-parametric test in order to prove my hypotheses which is simply showing that one independent variable significantly influences the dependent one. </p>
<p>... | g64779 | [
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<p>Is there a way to statistically compare r-squared across 2 groups using nested models in multigroup analysis? I know how to use lavaan to test various other parameters across groups (e.g. regression coefficients, intercepts, variances...etc), but I can't find documentation for how to compare R-squared. </p>
<p>Here... | g64780 | [
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<p>I just got my Bachelors Degree in mathematics and I've begun working with a company that is requiring some extensive data analysis and statistical inquiry.</p>
<p>I took several statistics courses in college as well as two grad courses but I found that my education was very theory driven.</p>
<p>I was wondering if... | g64781 | [
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<p>Is there some way to create a bivariate distribution from a fitted copula and 2 marginals? I have finally managed to fit a copula to my stock returns using the package fCopulae and would like to calculate the VaR of a portfolio consisting of these two stocks. As far as i can tell, this can be done by simulating from... | g206 | [
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<p>If we wish to conduct a paired t-test, the requirement is (if I understand correctly) that the <strong>mean</strong> difference between the matched units of measurement will be distributed normally.</p>
<p>In paired t-test, that is articulated (AFAIK) in the demand that the difference between the matched units of m... | g64782 | [
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<p>I have a dataset consisting of users, each with a number of items (ranging from 1 to 100). The end-goal is for each user to be able to predict the ranking the of the items according to some other measure of popularity. </p>
<p>Let's assume I have train an algorithm to do this and can compare my results to the actua... | g23078 | [
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<p>When running a repeated measures ANOVA in SPSS, it's possible to 'Save' the residuals as new variables in the data editor.</p>
<p>But the values output do not match the residuals given in R, and seem to be residuals for a between-subjects model. Unless I am missing something? Is SPSS giving the wrong residuals?</p>... | g42626 | [
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<p>The 'fundamental' idea of statistics for estimating parameters is <a href="http://en.wikipedia.org/wiki/Maximum_likelihood">maximum likelihood</a>. I am wondering what is the corresponding idea in machine learning.</p>
<p>Qn 1. Would it be fair to say that the 'fundamental' idea in machine learning for estimating p... | g412 | [
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<p>I have a bunch of vectors from two groups, $X$ and $Y$, and each vector in either $X$ or $Y$ groups has $m$ elements. Now I have $X_{1},\ldots,X_{8}$ and $Y_{1}, \ldots, Y_{8}$ in each group, and would like to compare/test the difference between the two groups. From the <a href="http://en.wikipedia.org/wiki/Hotellin... | g64783 | [
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<p>The least squares formula, $\beta = (X'X)^{-1}X'Y$ can be recursively formulated as
\begin{align}
\beta_t &= \beta_{t-1} +\frac{1}{t}R_t^{-1}x_t'(y_t-x_t\beta_{t-1}),\\
R_t &= R_{t-1}+\frac{1}{t}(x_t'x_t-R_{t-1}),
\end{align}
where $\beta_{t}$ denotes the least squares estimate using the observations $1,\ld... | g64784 | [
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<p>It is often recommended to take the square root when you have count data. (For some examples on CV, see @HarveyMotulsky's answer <a href="http://stats.stackexchange.com/questions/11359/what-could-be-the-reason-for-using-square-root-transformation-on-data/11366#11366">here</a>, or @whuber's answer <a href="http://st... | g42788 | [
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-... |
<p>I am using the <strong>pearsonFitML</strong> function in the <strong>PearsonDS</strong> package to do maximum likelihood estimation of parameters in R. </p>
<p>I am particularly interested in fitting <strong>Pearson Type 5</strong> distributions to my data. Does anyone know how I can 'fix' this function so it only ... | g42627 | [
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<p>In the case of multiple regression where I have dependent variable Y and two predictors X1 and X2 I would like to make a plot of their relationship before fitting a regression, however the plot function only allows the plotting of two variables at a time. for example <code>plot(x, y)</code> how can I look at the ove... | g64785 | [
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<p>What is $\rho_{XY}$ when $X=0$ and $Y=0$? For all $X=Y$, $\rho_{XY}=1$ and this should be no exception. But using the following: $$\rho_{XY}=\frac{E(XY)-E(X)E(Y)}{\sqrt{Var(X)Var(Y)}}$$ yields a $\frac{0}{0}$ form. How do I take the limits or apply L'Hospital's rule to prove this equals 1?</p> | g64786 | [
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<p>I know the mean square error formula and how to compute it. When we talk about a regression we can compute the mean square error. However can we talk about a MSE for a classification problem and how to compute it?</p> | g23090 | [
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<p>The following is from Gelman & Hill 2007:</p>
<pre><code>Suppose that, for a certain population, we can predict log earnings from log
- A person who is 66 inches tall is predicted to have earnings of $30,000.
Every increase of 1% in height corresponds to a predicted increase of 0.8%
in earnings.
- The... | g22997 | [
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<p>Suppose we have a data set consists of, say, 5 or 10 observations. The only thing we know about this set is that it came from a positive right skewed distribution. </p>
<ul>
<li>How can we fit a probability distribution to this data?</li>
<li>Is there a paper or method (frequentist, Bayesian, nonparametric) that de... | g64787 | [
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<p>I have some data from neuroscience, to be more precise a set of data which represents the connections between brain cells (so called "axons"). These connections form a binary tree as depicted below. Interestingly when I look at the lengths of these edges (i.e. axons) at each depth, the lengths are lognormally distri... | g23094 | [
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0.03304744139313698,
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-0.07656961679458618,
0.015660280361771584,
-0.01848173514008522,
0.013420520350337029,
-0.020200515165925026,
-0.018832994624972343,
-0.007085980381816626,
-0.05516177415847778,
0.024017048999667168,
0.05238128453493118,
-0.... |
<p>In a Cox proportional hazards model with many variables, if the Schoenfeld residuals are not flat for one of the variables, does this invalidate the entire model or can just the poorly-performing variable be ignored? That is, interpret the coefficients for the other variables, but do not interpret the resulting coef... | g64788 | [
0.03111409582197666,
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0.005085519049316645,
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0.06759025156497955,
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0.02232782356441021,
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0.002859460422769189,
0.029891187325119972,
-0.0... |
<p>I want to do a power analysis for a equivalence design but with repeated measures. Does anyone have a suggestion on how to proceed? Also, I want some suggestion on testing the difference of the means with that design? </p> | g43726 | [
-0.029291220009326935,
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0.... |
<p>Can the weight initialization algorithm, known as the Nguyen-Widrow Algorithm, be used for a multi-layer perceptron neural network, which consists of more than one hidden layer? (like 6-4-4-3-2)</p>
<p>The <a href="http://www.stanford.edu/class/ee373b/nninitialization.pdf" rel="nofollow">paper</a> which introduces ... | g64789 | [
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0.015262638218700886,
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0.002860368462279439,
... |
<p>I have an agricultural ditch that was converted to a different geometry in 2002. I have one year of measured cross-section data on the ditch before construction. I have 3 years of measured cross-section data after construction (multiple columns arranged by year). </p>
<p>For each year, data were measured every 100 ... | g64790 | [
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0.009340249933302402,
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0.034307584166526794,
... |
<p>I asked something like this on math.stackexchange but it got no answers so I'm hoping for more enlightenment here (the other question is <a href="http://math.stackexchange.com/questions/248304/estimation-of-transition-probabilities-from-aggregate-data">this one</a>).</p>
<p>So: We have some number of people; each p... | g23099 | [
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-0.0... |
<p>I'm wondering what the difference is between:</p>
<ol>
<li>'predicted by residual plot' where I plot the residuals of the regression with the predicted values of the regression ;</li>
<li>the case where I plot the residuals with the predictor variables.</li>
</ol>
<p>Also I'm wondering how to make such a plot in R... | g64791 | [
0.048683758825063705,
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0.023762274533510208,
0.027538370341062546,
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0.015285437926650047,
0.017602527514100075,
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<p><strong>Context</strong>:<br>
Poisson point processes (<strong>PPP</strong>) are widely discussed in the literature.
In the following figure a framework to generate two-dimensional PPP is demonstrated. <strong>First</strong> the area being studied (part of space which can be in 1D, 2D, 3D, ..., in our example is a 2... | g16730 | [
0.05488942936062813,
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0.019563883543014526,
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0.0038094399496912956,
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-0.033872026950120926,
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0.03370724990963936,
0.022705581039190292,
-... |
<p>Im dealing with a VAR model where I also want to include exogenous variables. Based on my sampling, the exogenous variables in $t$ are independent from my other variables in $t$, but highly dependent on the other variables in $t-1$.</p>
<p>Could there be some serious error from an estimation point, like simultaneo... | g64792 | [
0.05058521404862404,
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0.05059388279914856,
0.02718351036310196,
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0.04360399767756462,
0.0009818357648327947,
0.03942517936229706,
0.0005016422946937382,
0.06... |
<p>Assuming equal variances determine the value of the best estimator of the variance of sample mean 1</p>
<p>From my exhibit/minitab I have</p>
<p>Sample 1: N = 1, Mean = 123.7, StDev = 19.8, SE Mean 5.5
T-Test of difference = 0, T-Value = 3.78, P-Value = 0.001, DF = 22
Both use Pooled StDev 23.1
Estimate for Differ... | g64793 | [
0.021170062944293022,
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0.009807023219764233,
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0.008542248979210854,
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0.019512895494699478,
0.03612759709358215,
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-0.019735781475901604,
0.020847171545028687,
-0.0024906208273023367,
0.038839295506477356,
... |
<p>How can the matrix of (ultrametric) distances be extracted from the result of <code>hclust</code> (or a dendrogram in general) in <code>R</code>?</p>
<p>The distance of two units in a dendrogram is defined as the smallest distance at which the two units (or the clusters which they are part of) merge.</p>
<p>For ex... | g64794 | [
0.03712446987628937,
0.04495299234986305,
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0.009445409290492535,
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0.06564227491617203,
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0.005420723930001259,
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-0.014508796855807304,
0.044000957161188126,
... |
<p>The problem:</p>
<p>I have a set of means and covariance matrices of a number of multivariant normal distributions, each having a class label. Then I get single data points, one after the other, to which I want to assign one of the class labels or the label 'None', if it is unlikely that the point belongs to any of... | g23102 | [
-0.012753698974847794,
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0.03543255105614662,
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0.0096137011423707,
0.010847968980669975,
0.004773717373609543,
0.04188918694853783,
0.01... |
<p>I am doing a study that is on 5 biomarkers a, b, c, d, e which are continuous variables. Having high a, b, c is bad and low d, e is bad for the body -- it causes bad outcomes. </p>
<p>Now, I collected data on a, b, c, d, e for 1 year for patients and also data on bad outcomes. I applied $\chi^2$ and Fisher test and... | g64795 | [
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0.017026226967573166,
0.010953031480312347,
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0.020260680466890335,
0.016693342477083206,
0.04290122911334038,
0.05145300179719925,
0.0... |
<p>If I was to run some untidy data through Google Refine ready for further analysis, how could I test if the operation has worked?</p>
<p>Say there are 1 million entries in the dataset. If I quickly scrolled down the data and checked a random entry to see if it had been correctly cleaned, how many would I have to che... | g64796 | [
-0.002572466153651476,
0.005070614628493786,
0.007398469839245081,
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0.005336842034012079,
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0.07586876302957535,
0.02177705243229866,
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-0.02778426930308342,
-0.029096979647874832,
0.03196209669113159,
0.04057161882519722,
-0... |
<p>I don't know how I'm getting this wrong.</p>
<p>Calculate P[ X > 7|X < 9 ]</p>
<p>So calculate P[X>7] given that X<9, I put X>7 as the numerator and X<9 as the denominator.</p>
<p>For X > 7, since the binomial distribution has .45920 I subtract that from 1, and use X <= 8 for X < 9, that value is .... | g23103 | [
0.06260652840137482,
0.07177934050559998,
0.011101123876869678,
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0.020947620272636414,
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0.029141398146748543,
0.026781834661960602,
-0.05124736204743385,
-0.035113606601953506,
0.0013010394759476185,
0.01719367317855358,
-0.... |
<p>Does using the bayesian estimator to complete SEM in Mplus mitigate some concerns with a limited sample size (n=120). I.e is this approach preferred over using the traditional ML estimator with associated p values?</p> | g23841 | [
-0.0016388139920309186,
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0.03666709363460541,
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0.029331540688872337,
0.031535785645246506,
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0.055351730436086655,
... |
<p>I am trying to estimate a Markov chain of second order (Markov chain that fulfills $P[X_t|X_{t-1},X_{t-2}]=P[X_t|X_{t-1},X_{t-2},...,X_{t-p}]$) using an AR(2) process. </p>
<p>Once I have simulated the chain I want to test the hypothesis of first order Markov property $H_0$ against second order Markov property $H_1... | g64797 | [
0.017349664121866226,
-0.06517314165830612,
-0.009755803272128105,
0.00855779554694891,
0.018514031544327736,
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0.010917529463768005,
0.003925232216715813,
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0.04745493456721306,
-0.007310804910957813,
0.0640449970960617,
0.044128209352493286,
0.0010... |
<p>I try to install rpy2 in my system,
(I compile R with --enable-R-shlib and with --enable-BLAS-shlib flags)
but when I try in python console</p>
<p>import rpy2
import rpy2.robjects</p>
<p>I got:</p>
<p>Traceback (most recent call last):
File "", line 1, in
File "/usr/lib/python2.6/dist-packages/rpy2/robjec... | g64798 | [
-0.0012783888960257173,
0.00020112913625780493,
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0.026415754109621048,
0.013601387850940228,
0.041280943900346756,
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0.04225052520632744,
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-0.01954781450331211,
-0.028994271531701088,
-0.01324515137821436,
-0.02673828974366188,... |
<p>I'm doing a simple AIC-based backward elimination model where some variables are categorical variables with multiple levels. These variables are modeled as a set of dummy variables. When doing backward elimination, should I be removing all the levels of a variable together? Or should I treat each dummy variable sepa... | g64799 | [
0.01163715124130249,
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0.023259827867150307,
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0.032405246049165726,
0.055965885519981384,
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0.013106336817145348,
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0.004645833279937506,
0.008073118515312672,
0.... |
<p>I am attempting to monitor the performance of a software package in order to identify when a change to the code base introduces a performance regression (a slow down in the code). My assumption is that if the performance of the data is unchanged, I'm essentially collecting samples from the same population, and I sho... | g23872 | [
0.029972940683364868,
0.00023248407524079084,
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0.08050615340471268,
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0.07842610776424408,
0.028735971078276634,
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-0.0455622673034668,
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0.044989682734012604,
0.00634982343763113,
0.04... |
<p>I have a table I want to convert into a graph (bar-graph or line-graph)</p>
<p>The first column has fixed values. Twenty different values are simulated for these fixed values and kept in the next columns. I want to plot a graph of the fixed column against all the different twenty simulated columns. </p>
<p>How do ... | g64800 | [
0.03764123097062111,
0.02043379284441471,
-0.012828048318624496,
-0.005362870171666145,
0.046135157346725464,
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0.009990060701966286,
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0.01680518127977848,
-0.018347958102822304,
0.052435342222452164,
0.017480431124567986,
-0... |
<p>Suppose $X\sim InvWishart(\nu, \Sigma_0)$. I'm interested in the marginal distribution of the diagonal elements $diag(X) = (x_{11}, \dots, x_{pp})$. There are a few simple results on the distribution of submatrices of $X$ (at least some listed at Wikipedia). From this I can figure that the marginal distribution of a... | g23108 | [
-0.006529719568789005,
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-0.03109794482588768,
-0.09002266824245453,
0.018085211515426636,
0.011670532636344433,
0.02016143873333931,
0.052151069045066833,
0.0072138989344239235,
-0.006548815406858921,
0.006762611214071512,
0.057509757578372955,
-0.006324667017906904,
... |
<p>I have noticed that there are a few implementations of random forest such as ALGLIB, Waffles and some R packages like <code>randomForest</code>. Can anybody tell me whether these libraries are highly optimized? Are they basically equivalent to the random forests as detailed in <a href="http://statweb.stanford.edu/... | g42818 | [
0.0052370913326740265,
0.0036765385884791613,
0.01712580770254135,
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0.003982312977313995,
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0.029928606003522873,
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-0.009345827624201775,
0.009444311261177063,
-0.002353208838030696,
0.04948538541793823,
... |
<p>Given a predicted variable (P), a random effect (R) and a fixed effect (F), one could fit two* mixed effects models (<a href="http://cran.r-project.org/web/packages/lme4/">lme4</a> syntax):</p>
<pre><code>m1 = lmer( P ~ (1|R) + F )
m2 = lmer( P ~ (1+F|R) + F)
</code></pre>
<p>As I understand it, the second model i... | g23882 | [
-0.009715067222714424,
-0.0387912318110466,
0.007192408200353384,
-0.00030287529807537794,
0.01321101188659668,
0.0164986252784729,
0.033175643533468246,
0.047162339091300964,
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-0.009016911499202251,
-0.05340681970119476,
0... |
<h2>Background</h2>
<p>I read about <a href="http://statprob.com" rel="nofollow">StatProb.com</a> from a comment on <a href="http://www.stat.columbia.edu/~cook/movabletype/archives/2011/03/why_edit_wikipe.html#comment-2187431" rel="nofollow">Andrew Gelman's Blog</a>.</p>
<p>According to the website, StatProb is:</p>
... | g23110 | [
0.009596958756446838,
0.03240801393985748,
-0.0016827307408675551,
0.018203355371952057,
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-0.022316260263323784,
0.02350691333413124,
0.040598705410957336,
-0.016541125252842903,
-0.005446026101708412,
0.06054874509572983,
-0.03235014155507088,
0.06340683996677399,
0.0... |
<p>I have $Y$ measurements per several Subjects and I'm studying impact of factor on $Y$ measurements. I've fit a lognormal mixed model with a random interaction, but I'm finding autoregressive dependence on residuals. However, some exploration suggests different temporal dependence per subject.</p>
<p>Can <code>lme()... | g64801 | [
0.0032385438680648804,
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0.007468776777386665,
0.06852299720048904,
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-0.006789808161556721,
0.019276181235909462,
0.006452230270951986,
0.022785255685448647,
-0... |
<p>I have a scenario where I have a User which likes 10 different sports and there is another user which likes 20 different sports. I need to find the correlation between them. What kind of correlations can be used in such a scenario. Any kind of guide would be helpful. I tried with Pearson correlation but was not help... | g37452 | [
0.058578576892614365,
0.002644771011546254,
0.01033037155866623,
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0.008066589944064617,
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-0.026847001165151596,
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-0.019812854006886482,
0.006493742577731609,
-0.003630697028711438,
0.037366826087236404,
... |
<p>I am carrying out an exploratory regression looking at the determinants of corporate governance. The final model is: Board independence= Country Dummies+ Democracy level+ Sector dummy+ log GDP+ logMarketCapitalisation
The dependant variable for board independence is a fraction, so going by this ( <a href="http://www... | g64802 | [
0.03558307886123657,
0.05624731257557869,
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0.05585672706365585,
0.010899504646658897,
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0.03791596740484238,
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-0.06958175450563431,
-0.0011010029120370746,
-0.005138592328876257,
0.01442778017371893,
0.... |
<p>When AR(1) is expressed as MA($\infty$), I can interpret it as: let's say my wage this year depends only on last year's wage and a random shock (my boss' mood). But last year's wage also depends on the year before that, and so on. Therefore, my current wage is a accumulation of my boss' moods across years, with long... | g64803 | [
-0.0070179826579988,
0.022680368274450302,
-0.007581702899187803,
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0.014055575244128704,
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0.07179737091064453,
0.04229412600398064,
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0.03993278741836548,
-0.0059453886933624744,
0.07019858062267303,
0.05927877873182297,
0.035... |
<p>My data:</p>
<ol>
<li>My outcome variable (Outvar) is binary (yes/no) </li>
<li>My explanatory variable (exvar) is also binary (yes/no)</li>
<li><p>I have 3 extra variables:</p>
<ul>
<li>Variable A is binary</li>
<li>Variable B is continuous but not normally distributed</li>
<li>Variable C is also continuous and h... | g64804 | [
0.05868252366781235,
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0.012223098427057266,
0.08504090458154678,
0.015513182617723942,
-0.042501695454120636,
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0.04089459404349327,
0.0002171891537727788,
0... |
<p>Imagine that we have a family of probability disributions with p.d.f $f_{\theta}(z)$ where
$\theta \in \Theta$. We also know that there is a linear dependence between parameters. As a consequence we can restrict to a nested model with p.d.f $f_{\theta}(z)$, where $\theta \in \Theta_{0} \subseteq \Theta$.</p>
<p>For... | g64805 | [
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0.010681970976293087,
0.060806818306446075,
0.05163939297199249,
-0.038659147918224335,
0.001481320010498166,
-0.03443523496389389,
0.03386848792433739,
-0.0004579278756864369,
0.... |
<p>I'm currently working with a dataset in R and my $B_0$ result is different when I run linear regression with & without converting the data into factors. And I want to understand what I'm doing wrong here.</p>
<pre><code># IV: Time
time = c(-1, -1, -1, 0, 0, 0, 1, 1, 1)
time.f = factor(time, levels=c(-1, 0, 1), ... | g23116 | [
0.03511117398738861,
-0.05751115083694458,
0.015088031999766827,
-0.030244015157222748,
0.02942609041929245,
-0.04023515433073044,
0.03584704175591469,
0.0394088514149189,
-0.03648864105343819,
-0.08742384612560272,
-0.00851480383425951,
0.08184409141540527,
-0.02056492306292057,
-0.021142... |
<p>I'd appreciate ideas about how to estimate the standardized mean difference (SMD) for two independent samples from each sample's size and middle three quartiles (i.e., median and 25th and 75th percentiles). This problem's context is a meta-analysis whose focal effect size is a post-intervention SMD between treatmen... | g64806 | [
-0.07285547256469727,
-0.046071071177721024,
-0.008555563166737556,
-0.07425668090581894,
-0.03202412649989128,
-0.02552672289311886,
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0.011906557716429234,
-0.0018713833997026086,
0.018593648448586464,
0.03793792799115181,
0.02749980054795742,
-0... |
<p>I have a double seasonal data. I wrote the following code to find the best fit model and find fitted values:</p>
<blockquote>
<p>orders <- read.csv("DataForR.csv", header = TRUE),
NumOrders <- orders$Orders,
> period <- orders$Period,
OrderTimeSeries <- msts(NumOrders,seasonal.periods=c(24,7*24... | g64807 | [
0.017016058787703514,
-0.04194720834493637,
-0.024530857801437378,
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-0.030967706814408302,
0.044308051466941833,
0.08693429082632065,
... |
<p>In the testing of normality, how would the 2 compare? Is one significantly better than the other?</p> | g64808 | [
0.04248199239373207,
-0.010480151511728764,
-0.003793311072513461,
0.03483304753899574,
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0.008429261855781078,
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-0.03075769729912281,
0.06305894255638123,
0.03134267032146454,
-0.0076351589523255825,
... |
<p>Hi I have data set with a set of variables and known class labels. I am trying to compare why a supervised approach will work theoretically better compared to a unsupervised approach for classification vs clustering in this case.
If I remove the labels from my data, I can cluster the vector of independent variable... | g29001 | [
0.02227938547730446,
-0.04366457834839821,
0.020263783633708954,
-0.030419183894991875,
-0.005145997274667025,
-0.037830568850040436,
0.05096159130334854,
0.004742493387311697,
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-0.03494725003838539,
0.05289837345480919,
0.02022179216146469,
0.04258958250284195,
0.0365... |
<p>I am working on an age estimation method using 4 types of biological measurements as age predictors. I am using RStudio.
So far, I have good results when I use linear regression (<code>lm(age~predictor)</code>), but I am encountering heteroskedasticity, and therefore cannot build prediction intervals for my models.... | g64809 | [
-0.009622817859053612,
-0.0346367284655571,
-0.024690808728337288,
-0.038981396704912186,
-0.045801274478435516,
0.0023992802016437054,
0.04015849530696869,
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0.001318012597039342,
-0.015016273595392704,
0.029926611110568047,
0.02261291816830635,
... |
<p>I would like to find a way to compare variance within and between site with differing numbers of observations. I have seen other posts on this, but they seem to focus on factor levels and I'm not sure that is appropriate with the number of sites (90) I have. Can someone suggest the best way to compare within and b... | g64810 | [
-0.014967485330998898,
-0.023401811718940735,
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0.005453655496239662,
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0.03248900547623634,
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0.0235572699457407,
0.016373775899410248,
0.024852439761161804,
-0... |
<p>Let's say we have four moments $(\mu_1, \mu_2, \mu_3, \mu_4)$ of a probabilty distribution of a random variable $X$ and the goal is to get the probability $\rm{P}(X \leq t)$ for a certain value of $t$.</p>
<p>How is possible to use the moments to <em>approximate</em> such probabilty? Is there a way to use the momen... | g64811 | [
-0.0022872197441756725,
-0.017748789861798286,
-0.0106595978140831,
-0.03455980867147446,
-0.021568411961197853,
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-0.05687689036130905,
-0.015463507734239101,
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0.049149274826049805,
-0.014441254548728466,
-0.032433170825242996,
0.04958181455731392,
... |
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