title: PC program implementing an alternative to the paired t-test which adjusts for regression to the mean.
abstract: In many biomedical research contexts, treatment effects are estimated from studies based on subjects who have been recruited because of high (low) measurements of a response variable, e.g., high blood pressure or low scores on a stress test. In this situation, simple change scores will overestimate the treatment effect; and the use of the paired t-test may find significant change due not to the treatment per se but, rather, due to regression towards the mean. A PC program implementing a procedure for adjusting the observed change for the regression effect in simple pre-test-post-test experiments is described, illustrated, and made available to interested readers. The method is due to Mee and Chua (Am Stat, 45 (1991) 39-42) and may be considered as an alternative to the paired t-test which separates the effect of the treatment from the so-called regression effect.
authors.affiliation: Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor 48109.
authors.forename: C J
authors.initials: CJ
authors.lastname: Kowalski
authors.forename: E D
authors.initials: ED
authors.lastname: Schneiderman
authors.forename: S M
authors.initials: SM
authors.lastname: Willis
mesh_terms: D000293:Adolescent; D001794:Blood Pressure / Q000502:physiology; D016001:Confidence Intervals; D004521:Educational Measurement; D004522:Educational Status; D005431:Florida; D006801:Humans; D008432:Mathematical Computing; D008838:Microcomputers; D012044:Regression Analysis; D012984:Software; D012985:Software Design; D016896:Treatment Outcome