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# Cross Validated : Recent Questions and Answers

## How to test consistency of responses?

I am analyzing data from several trials where individuals were submitted to different stimuli and a biological response was measured. Some individuals participated in more than one trial where the...

## How can I understand these variograms?

Using grf function from R package geoR, I simulated 6 replicates (each with 1000 samples) of a Gaussian random field on [0, 1] x [0, 1], with zero mean, zero...

Asked on 01/07/2022 by Zheyuan Li

## Trying to wrap my arms around copulas

This topic is dense with notation that makes things a bit confusing. But is this the correct interpretation? Suppose we have two jointly distributed random variables – $X$ ...

## Justification for and optimality of $R^2_{adj.}$ as a model selection criterion

In a recent thread, use of adjusted $R^2$ ($R^2_{adj.}$) is mentioned in the context of model selection, e.g. The adjustment was invented as a solution to problems...

## How to interpret results of mixed longitudinal model in R?

So I'm not too familiar with mixed models, but wondering about the following:library(reshape2)library(lme4)library(lmerTest)#Simulate longitudinal dataN <- 25t <- 2x <-...

## $E(xy)<infty$ proof

I am reviewing the best linear projection properties proof in Hansen's book on econometrics. Specifically, the proof according to which $E(xy)<infty$. For this, it is assumed that $E(y^2)<infty$...

## Calculating eigen values from principal components and deciding on the number of principal components?

I calculated PCs for my samples and I am showing here data frame that has samples as my rows and PCs as my columns. My question is in order to...

## Question on method for analysis

First of all, I have begun researching as a masters student and I am forcing myself on more statistical validation and significance testing - this is not my strong suit....

Asked on 01/05/2022 by Paul Kumar

## Selecting uncorrelated samples from a set of bulk data that contains correlated and dependent samples

i have a set of data that is generated by expensive computational model evaluations, on a total data set of 10000 samples in 40 dimensions. This sample data set is...

## Test for significance of peaks (maximum) in time series

I have a time series of values, something like this: value2015-12-01 ...