Assignment:
A marketing survey is to be planned to estimate the proportion of all customers who would subscribe to a new pay-per-view service that a cable TV plans to offer. The sample size for the survey is to be decided to estimate this proportion within a margin of error 2 percentage of points using a 95% confidence interval.
a) If the a priori guess of the proportion was 20%. What sample size should be used?
If no a priori guess of the proportion was available, what sample size should be used? Why is this sample size larger than that found in part (a)?