# All Questions

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### Looking for an adaptMCMC (R package for adaptive MCMC sampling) tutorial

I need to fit a very complex Bayesian hierarchical model and I want to use the adaptMCMC package of Andreas Scheidegger to do the posterior sampling. I can only find the adaptMCMC package reference ...
19 views

### Can probability be used to calculate (any?) effect size measurement? Version 2

A similar question has been answered, but I reframed here to remove the ambiguity in that question as to what I'm after... (as a survival analysis was not performed) For example, some studies report ...
33 views

### Unknown number of colours Bernoulli Urn

Okay, so, in the traditional Bernoulli Urn problem, we have an urn with a number N, possibly infinite, of coloured balls, and there are k possible colours. That one I grok. However, what if I don't ...
37 views

### Scaling hinge loss in SVM

Recall the functional of primal SVM problem: $\|w\|^2 + C \sum_i \xi_i \to \min$. Suppose I have 1000 training objects, and want to find optimal $C$ by 2-fold cross-validation. As a result of ...
6 views

### How to find entropy of vocabulary terms in multilabel document classification problem?

I have 5 million of document s with varying number of labels for each. I intent to find entropy value for selecting discriminative terms to degrade the size of vocab. However, having that multiple ...
43 views

### Calculate $E(X)$ and $\sigma(X)$ for a simple urn problem

In a box there are 4 red and 7 green balls. A random sample of 5 of the balls is made. Let the number of red balls in the sample be $X$ (a random variable). Calculate $E(X)$ and $\sigma(X)$
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### Role of orthogonal constraints (X^TX=I) in linear discriminant analysis?

What is the role of the orthogonal constraints in Linear Discriminant Analysis? Why would it work/not work if the fraction of the traces is maximized without that constraint? Wouldn't its still ...
60 views

### How to find/estimate probability density function from density function in R

Suppose that I have a variable like X with unknown distribution. In Mathematica, by using SmoothKernelDensity function we can ...
7 views

### What are methods/software packages to create temporal matrices for agricultural practices?

I would like to create a temporal model showing the likelihood (I am sure this is not used in the correct context) that certain size avocados grow from smallest, small, bigger, biggest. I have ...
21 views

### Correct time lag in regression

Let's say you have two time series. you know they are highly correlated with the right time lag. Is there a function that's used to calculate the correct time lag, or do you just have to run a bunch ...
18 views

### spss covariates variables in regression model

in the regression model in the spss statistic software can you explain me what are the covariates variables? if i want express a model like ...
58 views

### In hypothesis testing, does a p-value less than alpha always mean you reject NH?

I have learned that a p-value that is less than alpha means you reject the null hypothesis. But this seems to only make sense in the case of lower tail tests. What do you do for upper tail tests?
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### How to interpret the lasso selection plot [duplicate]

I did lasso selection using lars::lars(), then I got this plot. I have no idea how to interpret it: Could anyone provide a brief explanation? Why does it plot ...
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### Predicting Naive Bayes model in R on a test data with a single record

I built a naivebayes model using the Housevotes84 data(discrete data) in mlbench package- model <- naiveBayes(Class~., data=HouseVotes84) I took one record ...
18 views

### Can probability be used to calculate (any?) effect size measurement?

For example, some studies report the probability of survival, on a scale of 0-1, with SE, and sample sizes for two treatments, rather than the mean and SD. Is there a sensible way to use the ...
20 views

### Ordinal model comparison: lower deviance but lower accuracy, is this possible?

I am performing ordinal regression (6 response categories) on a large dataset (>15000 points) and comparing two models, one with one predictor X1 (Model 1) and the other with two predictors X1 and X2 ...
32 views

### How to use Ridge Regression for classification? (Or other suggestions)

I have a sparse regression problem (Sparse because a few inputs are factors so we have a lot of columns of 1s and 0s). I am thinking of Ridge Regression because of the sparsity, but also because a lot ...
35 views

### Direction of the z-scores in randomForest

I wonder if someone could help me with the interpretation of the "z-scores" (%IncMSE) in the random forest approach. I am using a randomForest library in R. Specifically, I am not sure whether the ...
If parameter p ~ Beta(1,1), this would reflect we know nothing about parameter $p$. Generalizing to the multivariate case, how would the same be said about a vector $P$ of probability parameters ...