TESTR: A Microcomputer Algorithm for Generating Bivariate Distributions to Fit Specified Relationships
Abstract
Computer Program ExchangeTESTR: A Microcomputer Algorithm for Generating Bivariate Distributions to Fit Specified Relationships SAGE Publications, Inc.1986DOI: 10.1177/014662168601000205 Edwin T. IIICornelius University of South Carolina Description It is often necessary to be able to generate observed cases according to a bivariate distribution with a known population correlation. This capability is essential for monte carlo work in a variety of areas, and is also useful for instructors of statistics in order to generate examples for teaching purposes. TESTR is an interactive program that allows users to do this on a microcomputer. TESTR uses the random number function (RND) available in BASIC, and applies the correction specified by Gilder (1980, p. 30) to produce normally distributed z scores. Each z score is then used to generate a matching score such that the resulting bivariate distribution fits the degree of correlation specified by the user. If needed, TESTR will also produce additional "error-perturbed" scores, such as would result in producing "observed scores" from "true scores." These error scores represent errors of measurement, and are generated when the user specifies a desired degree of reliability in the variables. The program prompts the user to enter the degree of correlation required, the number