A regional hardware chain is interested in estimating the proportion of their customers who own their own homes. There is some evidence to suggest that the proportion might be around 0.70. Given this, what sample size is required if they wish a 90 percent confidence level with a margin of error of ±.025?
A) About 355
B) Approximately 910
C) Almost 1,300
D) 100

Question

Quizplus · Accepted Answer

To calculate the sample size for a proportion with a given confidence level and margin of error, use the formula: n = (Z^2 * p * (1-p)) / E^2. For a 90% confidence level, Z is approximately 1.645. With p = 0.70 and E = 0.025, the calculation gives a sample size of approximately 910.

A Regional Hardware Chain Is Interested in Estimating the Proportion