Optimum sample size allocation to minimize costor maximize power for the two-sample trimmedmean test

摘要

When planning a study, sample size determination is one of the most important tasksfacing the researcher. The size will depend on the purpose of the study, the costlimitations, and the nature of the data. By specifying the standard deviation ratio and/orthe sample size ratio, the present study considers the problem of heterogeneousvariances and non-normality for Yuen's two-group test and develops sample sizeformulas to minimize the total cost or maximize the power of the test. For a givenpower, the sample size allocation ratio can be manipulated so that the proposedformulas can minimize the total cost, the total sample size, or the sum of total samplesize and total cost. On the other hand, for a given total cost, the optimum sample sizeallocation ratio can maximize the statistical power of the test. After the sample size isdetermined, the present simulation applies Yuen's test to the sample generated, andthen the procedure is validated in terms of Type I errors and power. Simulation resultsshow that the proposed formulas can control Type I errors and achieve the desiredpower under the various conditions specified. Finally, the implications for determiningsample sizes in experimental studies and future research are discussed.