© 1978 by Biometrika Trust
Determination of sample size for testing the relation between an incident and a set of random variables in a sample survey
Department of Statistics, University of Florida Gainesville
It is often necessary to determine if, and to what extent, an incident A is related to a set of environmental random variables X = (X1, ..., Xk)'. In this paper we assume that in the general population, X is normally distributed with mean µ and covariance matrix 
. A sample of X will be taken from the incident and nonincident groups, and, assuming that the incident rate p is approximately a linear function of X1 ..., Xk, we can determine the sample sizes for detecting the dependence between A and X without any prior knowledge of the unknowns µ and . Let p1 be the average incident rate in the population and 
and po be two given numbers with po < p1. The sample size is then determined so that the dependence relation between A and X will be detected with small error if a fraction or more of the population live in an environment which has incident rate no greater than po.
Key Words: Correlation analysis • Hotelling's T2 test • Selection of sample size