has part
has_specified_input
has_specified_output
achieves_planned_objective
p-value
median calculation
false positive rate
Brown Forsythe test
Orlaith Burke
Alejandra Gonzalez-Beltran
Philippe Rocca-Serra
adapted from Wikipedia and Brown, M. B., and A. B. Forsythe. 1974a. The small sample behavior of some statistics which test the equality of several means. Technometrics, 16, 129-132.
http://www.statmethods.net/stats/anovaAssumptions.html
The hovPlot( ) function in the HH package provides a graphic test of homogeneity of variances based on Brown-Forsyth. In the following example, y is numeric and G is a grouping factor. Note that G must be of type factor.
# Homogeneity of Variance Plot
library(HH)
hov(y~G, data=mydata)
hovPlot(y~G,data=mydata)
the Brown Forsythe test is a statistical test which evaluates if the variance of different groups are equal. It relies on computing the median rather than the mean, as used in the Levene's test for homoschedacity.
This test maybe used to, for instance, ensure that the conditions of applications of ANOVA are met.
homoskedasticity test
equal variance testing objective
ready for release