cramersv {confintr}

Cramer's V

Description

This function calculates Cramer's V, a measure of association between two categorical variables.

Usage

cramersv(x)

Arguments

x

The result of stats::chisq.test(), a matrix/table of counts, or a data.frame with exactly two columns representing the two variables.

Details

Cramer's V is a scaled version of the chi-squared test statistic \chi^2 and takes values in [0, 1]. It is calculated as \sqrt{\chi^2 / (n \cdot (k - 1))}, where n is the number of observations, and k is the smaller of the number of levels of the two variables.

Yates continuity correction is never applied. So in the 2x2 case, if x is the result of stats::chisq.test(), make sure no continuity correction was applied. Otherwise, results can be inconsistent.

Value

A numeric vector of length one.

References

Cramer, Harald. 1946. Mathematical Methods of Statistics. Princeton: Princeton University Press, page 282 (Chapter 21. The two-dimensional case).

See Also

ci_cramersv()

Examples

cramersv(mtcars[c("am", "vs")])