1. Question: 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 th...
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? 385
5. Question
Suppose a clothing store wants to determine the current percentage of
customers who are over the age of forty. How many customers should the
company survey in order to be 92% confident that the estimated (sample)
proportion is within 3 percentage points of the true population proportion of
customers who are over the age of forty? 852
6. 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
5 percentage points of the true population proportion of customers who keep up with regular
vehicle maintenance? 271
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