Chapter 7 and One-Way and Higher Designs for Independent Groups 339 SW . J Results in Rao, Kaplan, & Cochran (1981) suggest estimating WI with s w = ¯ 2 WI = ^ wb ^ 2 , wb + s w ^ 2 ¯ 2 where wb = ^ 2 j 1 J n j n j + 1 ¯ j ( Y j ~ - Y ) 2 , = and ~ Y = ¯ j Y j j . Wilcox (1994c) compared the bias and mean squared error of WI to two alternative estimators ^ and recommended WI . When WI is close to zero, some type of bias reduction method ^