What is the chi-squared test? The chi-squared test, often written as χ 2 test, is a statistical hypothesis test used in the analysis of categorical variables to determine whether observed data are ...

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A statistical test that allows one to determine whether observed quantities of a specific characteristic differed from the expected value purely by chance.

When an effect size estimate from an earlier study is available, it is common practice to calculate a sample size for a future study by postulating that the true effect size equals the point estimate ...