Statistical Inference for a Ratio of Dispersions Using Paired Samples
Wilcox (1990) examined the Type I and Type II error rates for several robust tests of H0: σ12/σ22 = 1 in paired-data designs and concluded that a satisfactory solution does not yet exist. A confidence interval for a ratio of correlated mean absolute deviations is derived and performs well in small sample sizes across realistically nonnormal distributions. When used to test a hypothesis, the proposed confidence interval is almost as powerful as the most powerful test examined by Wilcox.
Bonett, Douglas G.; and Seier, Edith. 2003. Statistical Inference for a Ratio of Dispersions Using Paired Samples. Journal of Educational and Behavioral Statistics. Vol.28(1). 21-30. https://doi.org/10.3102/10769986028001021 ISSN: 1076-9986