title: Evaluating group distributional characteristics: why psychophysiologists should be interested in qualitative departures from the normal distribution.
abstract: Real data often do not approximate the normal distribution. Under nonnormal conditions, psycho-physiologists who use parametric statistics may be testing with inadequate power and/or testing a measure of location (i.e., the mean) that does not represent the desired portion of the distribution for statistical comparison. The purpose of this paper is: first, to provide psycho-physiologists with a method to investigate group distributional characteristics; second, to evaluate the distributional characteristics of heart period and respiratory sinus arrhythmia in human adults and newborns; third, to demonstrate the increased statistical power that can accompany the selection of an alternative statistical analysis for nonnormal data. Suggestions are provided on how to analyze nonnormal data.
authors.affiliation: Department of Psychology, Adams State College, Alamosa, Colorado 81102, USA. tcriniol@adams.edu
authors.forename: T C
authors.initials: TC
authors.lastname: Riniolo
authors.forename: S W
authors.initials: SW
authors.lastname: Porges
mesh_terms: D000328:Adult; D003627:Data Interpretation, Statistical; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007206:Individuality; D008297:Male; D015233:Models, Statistical; D009010:Monte Carlo Method; D011603:Psychophysiology / Q000706:statistics & numerical data*; D012016:Reference Values