Showing papers by "Per B. Brockhoff published in 2002"

The design of replicated difference tests

Abstract: We show that adding replications in replicated difference tests results in larger power and smaller variance when the number of assessors is fixed. On the other hand, when the number of total assessments is fixed, the power usually decreases and the variability increases whenever replications are considered instead of different assessors. The appropriate numbers of assessor needed to gain the same power and variability, respectively, when replications are used will be given. It is shown that the number of assessors might indeed be reduced, but this has to be paid for by an increasing total number of assessments. We show that two key models, namely the mixture binomial and a corrected version of the Beta-binomial model, are quite similar with respect to the properties of interest. We provide tables from tvhich, according to her/his requirements, the investigator might find an appropriate setting with respect to the number of assessors and replications.