MATH 225N Week 6 Assignment: Estimating Sample Size for a Population Proportion

MATH 225N Week 6 Assignment: Estimating Sample Size for a Population Proportion 1. Suppose an automotive repair company wants to determine the current percentage of customers who keep up with regular vehicle maintenance. How many customers should the company survey in order to be 90% confident that the estimated (sample) proportion is within 2 percentage points of the true population proportion of customers who keep up with regular vehicle maintenance? 423 2. Suppose a shoe store wants to determine the current percentage of customers who are males. How many customers should the company survey in order to be 90% confident that the estimated (sample) proportion is within 3 percentage points of the true population proportion of customers who are males? 752 3. Deborah wants to estimate the percentage of people who eat fast food at least once per week. She wants to create a 90% confidence interval which has an error bound of at most 3%. How many people should be polled to create the confidence interval? 752 4. Suppose an automotive repair company wants to determine the current percentage of customers who keep up with regular vehicle maintenance. How many customers should the company survey in order to be 95% confident that the estimated (sample) proportion is within 5 percentage points of the true population proportion of customers who keep up with regular vehicle maintenance?