A researcher who wishes to study the effects of a prenatal breastfeeding education program on the length of time African-American inner-city women breastfeed infants learns that 70% of women in the target population are unmarried.To achieve stratified random sampling in a sample of 50 subjects,the researcher will
A) conduct the study using unmarried subjects only.
B) randomly assign all subjects to control versus experimental groups.
C) select a random sample of 35 unmarried and 15 married subjects.
D) select 25 subjects who are married and 25 who are not married.

Question

Quizplus · Accepted Answer

Stratified random sampling is used when the researcher knows some of the variables in the population that are critical for achieving representativeness,such as marital status.In this case,subjects are randomly selected,but stratification by marital status to match the target population proportions helps to improve generalizability of the findings.Using only married subjects makes the results ungeneralizable to unmarried subjects.Randomly assigning subjects without stratification does not make the groups representative.Having equal numbers from each group is possible if subjects are randomly assigned and not selected.

A Researcher Who Wishes to Study the Effects of a Prenatal