PROBLEM:

You are interested in interviewing people who own both a cat and a dog.The estimated incidence rate in the population is 7%.You expect a survey completion rate of 55%.

(1) What final sample size would be required to obtain a statistical estimate of a parameter with an expected proportion of 50% within +/- 3% with 95% confidence?

(2) Based on the incidence rate and expected completion rate, what initial sample size (e.g., how many invites) is required to obtain the necessary final sample size for analysis?