Sample Sizes in Chi-Square Tests for Measuring Advertising Effectiveness.

The concepts of alpha error, beta error, power and alternative hypotheses are first developed for a simple percentage problem in market research. These concepts are then used to explain the method of calculating simple size in the multi-cell case using the non-central Chi-Square distribution. The development is by means of an advertising research problem for delineating "different" geographical trading areas and the sample size necessary to detect differences of given magnitudes. [ABSTRACT FROM AUTHOR]