Some useful nonparametric tests for ordered alternatives in randomized block experiments

Abstract

Testing for ordered alternatives in randomized block designs has been a problem of interest for almost three decades (Jonckheere (1954)). Three classes of rank tests have evolved—tests based on “within-blocks” rankings (W-tests), tests based on “ranking after alignment” within blocks (RAA-tests), and tests based on “among-blocks” rankings (A-Tests). This paper focuses on the latter. A simplified version of the Skillings-Wolfe generalized Purl test (1977) is suggested and two very useful A-tests—a generalized Johnson-Mehrotra “Optimal contrast” procedure and a generalized Tryon-Hettmansperger rank test—are developed. These procedures are compared and contrasted with other recent competitors presented by Skllllngs and Wolfe (1978) and by Salama and Quade (1981).

Keywords:

• ordered alernatives
• power and “practical power”
• nandomized block design
• block mights