On comparing means in the paired case with incomplete data on both responses

Abstract

SUMMARY

Five procedures for testing the equality of two correlated means with incomplete data on both responses are compared by using Monte Carlo studies; three procedures were suggested by Lin & Stivers (1974) and two are suggested in this paper. The results are that the two tests based on a modified maximum likelihood estimator are to be preferred, the one due to Lin & Stivers when the number of complete pairs is large and the one proposed in this paper otherwise, provided the variances of the two responses do not differ by much. When the correlation between the two responses is small two other tests may be used; a test proposed in this paper when the homoscedasticity assumption is not strongly violated, and a Welch type statistio suggested by Lin & Stivers otherwise.