I have five groups of data and I want to test if their variance is significantly different or not. The data are normally distributed and I do not have any repeated measurements in any groups. What sort of analysis should I use?
Tukey's test compares the means, but how can I compare their variances?
For example I have 3 groups A, B and C. In groups A, B and C I have 30, 50 and 20 observations (which are stored as double-precision numeric variables in R).