# Proportion in marketing survey

Question 4 (20 Points): 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? (10 pts.)

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)? (10 pts.)

https://brainmass.com/statistics/sample-size-determination/proportion-marketing-survey-10865

#### Solution Preview

a) If the a priori guess of the proportion was 20%. What sample size should be used? (10 pts.)

The sample size formula uses three key factors:

(1) the alpha level, the level of acceptable risk the researcher is willing to accept that the true margin of error exceeds the acceptable margin of error; i.e., the probability that differences revealed by statistical analyses really do not exist; also known as Type I error.

The alpha level used in determining sample size in this survey is.05. In the formula, the alpha level is incorporated into the formula by utilizing the t-value for the alpha level ...

#### Solution Summary

Question 4 (20 Points): 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? (10 pts.)

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)? (10 pts.)