Fig. 4.
Family-wise error rates with three covariates: family-wise error rates of the robust test procedure (WB), random field F test (RF-F), and the χ2 field for the Wald-type test statistics (RF-C) under the linear model (19) with three covariates (Covs) in (21). We consider sample sizes of 10, 20, and 40 subjects, four differing correlations ρ = 0, 0.25, 0.5, and 0.75, and two differing distributions, including homogeneous variance (HMV) and heterogeneous variance (HTV), at the 5% significance level. (a) n = 10, 3 Covs, and HMV; (b) n = 20, 3 Covs, and HMV; (c) n = 40, 3 Covs, and HMV; (d) n = 10, 3 Covs, and HTV; (e) n = 20, 3 Covs, and HTV; (f) n = 40, 3 Covs, and HTV.