Categorical Data

Abstract

In many experiments and in almost all surveys, many if not all of the results fall into categories rather than being measurable on a continuous or ordinal scale: e.g., male vs. female; black vs. Hispanic vs. oriental vs. white; in favor vs. against vs. undecided. The corresponding hypotheses concern proportions: “Blacks are as likely to be Democrats as they are to be Republicans.” Or, “the dominant genotype ‘spotted shell’ occurs with three times the frequency of the recessive.”