In multiple hypotheses testing, it is important to control the probability of rejecting "true" null hypotheses. A standard procedure has been to control the family-wise error rate (FWER), the probability of rejecting at least one true null hypothesis. For large numbers of hypotheses, using FWER can result in very low power for testing single hypotheses. Recently, powerful multiple step FDR procedures have been proposed which control the "False Discovery Rate" (expected proportion of Type I errors). More recently van der Laan, Dudoit and Pollard (2004) proposed controlling a generalized family-wise error rate k-FWER (also called gFWER(k)), defined as the probability of at least (k+1) Type I errors (k=0 for the usual FWER). Lehmann and Romano (2005) suggested both a single-step, and a step-down procedure for controlling the generalized family-wise error rate. They make no assumptions concerning the p-values of the individual tests. The step-down procedure is simple t...
Paul N. Somerville, Claudia Hemmelmann