A Robust Test for Homoscedasticity in a Two-Way Layout

This paper discusses tests for homogeneity of row-variances in a two-way classification. Parametric tests for this problem are shown to be highly sensitive to departures from the normality assumption. Levene's robust tests tend to be rather liberal when the number of rows exceeds the number of columns. A modification is suggested which improves the approximation for this situation, while retaining the desirable robustness property.