Most useful statistical techniques in six sigma DMAIC are hypothesis testing and interval estimation. So this paper reviews and derives sample size formula by considering significance level, power of detectability and effect difference. The quality practioners can effectively interpret the practical and statistical significance with the rational sample sizing.

This study examined processing of L2 English relative clauses by testing the Filler-Gap Hypothesis (Hawkins, 1999; O"Grady 1997). For that goal, we partially replicated Diessel and Tomasello (2004), who examined L1 acquisition of relative clauses by English-and German-speaking children. The Filler-Gap Hypothesis states that the structural distance between head and gap determines the processing difficulty pertained within relative clauses. Taking this hypothesis as a theoretical starting-point, we used an elicited imitation task to tap 48 L2 learners" knowledge of English relative clauses. The results of the study demonstrated that subject relatives retained greater accuracy scores than object relatives, which in turn retained greater accuracy scores than indirect object and oblique relatives. These results were largely consistent with the predictions made by the FGH, but only partially consistent with Diessel and Tomasello"s L1 data.