Question

A stratified random sample was conducted to examine diabetes risk factors in Community X (N=3000). This small southeastern community only had non-Hispanic (NH) black (10%) and NH white (90%) residents. An investigator first stratified the population by race and then randomly selected an equal number of NH blacks (n=200) and NH whites (n=200) for the study.

Calculate selection probabilities (n/N) and corresponding sampling weights for NH blacks and NH whites. What is the importance of using sampling weights?

Race                Sampling fraction (n/N)          Sampling weight (1/p = 1/(n/N))

NH Black       

NH White      

Answer 1