STATISTICAL ANALYSES FOR R-INDEX.

R -index is an important statistic for testing and measuring product effects. The validation and merits of R-index are to a great extent due to the fact that it is closely related to the famous Mann–Whitney U statistic. Based on this fortunate relationship, statistical analyses for R-index are explored. The statistical analyses include estimations of R-index and its null and nonconditional variances with and without assuming continuity of data; difference and similarity tests using R-index; powers and sample sizes for the tests; linking R-index with Thurstonian δ (or d′). The new techniques developed in the paper extend greatly the original R-index analysis for categorical ratings data. It is expected that the recognition of the profound theoretical origin of R-index and the available statistical analyses for R-index will provide the impetus for the resurgence of interest in using R-index in sensory and consumer researches. [ABSTRACT FROM AUTHOR]