How do I test for unequal variances in mixed model?
I want to test if the measurement (intermediate) precision from two different labs are different. My data usually consist of the same sample being measured k times per day, across n days in each of the two labs. I analyze the data using Fit Model with lab as fixed effect, and Day as random effect. I would like to compare the total variation (within and between days) between the two labs - somethin...