leveneTests: Levene Tests of Homogeneity of Variances
Description
This function extends leveneTest to a multivariate
response setting. It performs the Levene test of homogeneity of variances
for each of a set of response variables, and prints a compact summary.
Usage
leveneTests(y, group, center = median, ...)
Value
An object of classes "anova" and "data.frame", with one observation
for each response variable in y.
Arguments
y
A data frame or matrix of numeric response variables in a
multivariate linear model.
group
a vector or factor object giving the group for the
corresponding elements of the rows of y
center
The name of a function to compute the center of each group;
mean gives the original Levene's (1960) test; the default,
median, provides a more robust test suggested by Brown and Forsythe (1974).
Levene, H. (1960). Robust Tests for Equality of Variances. In
Olkin, I. et al. (Eds.), Contributions to Probability and
Statistics: Essays in Honor of Harold Hotelling, Stanford University Press,
278-292.
Brown, M. B. & Forsythe, A. B. (1974). Robust Tests For Equality Of
Variances Journal of the American Statistical Association, 69,
364-367.