A store manager wants to estimate the proportion of customers who spend money in this store. How many customers are required for a random sample to obtain a margin of error of at most 0.075 with 80% confidence?Find the z-table here.

Because the proportion is unknown, use 0.50 for the most conservative estimate. For 80% confidence, the critical z-value is about 1.282, so the required sample size is n = (1.282² × 0.50 × 0.50) / 0.075² ≈ 73. Round up to ensure the margin of error is no more than 0.075. The correct choice is 73 customers.

AI-written and checked against the verified answer.