title: Analysis of Data that is in the Form of Categories.
abstract: This is the fifth installment in a series of articles devoted to a simplified description of statistical techniques. Here we are concerned with the analysis of nominal and ordinal categorical variables where the outcomes are counts or frequencies of events that are observed in an experiment. Examples are given for chi-square analysis of 2 * 2 tables, for the calculation and interpretation of odds ratios, and for the estimation of sample sizes in experiments where outcomes are categorical.
authors.affiliation: a LSU Medical Center New Orleans , LA 70112 , USA.
authors.forename: R
authors.initials: R
authors.lastname: Mera
authors.affiliation: b Clinical Trials and Biometry Unit , LSU Eye Center , New Orleans , LA 70112 , USA.
authors.forename: H W
authors.initials: HW
authors.lastname: Thompson
authors.affiliation: c Section of Endocrinology, Department of Medicine , LSU Medical Center , New Orleans , LA 70112 , USA.
authors.forename: C
authors.initials: C
authors.lastname: Prasad
keywords: 2 * 2 table; Categorical data; Chi-square; Nominal data; Odds ratio; Ordinal data