A survey of 144 retail stores revealed that the average price of a DVD was $375 with a standard error of $20. What is the 99% confidence interval to estimate the true cost of the DVD?

Question

Quizplus · Accepted Answer

The 99% confidence interval is given by:x̄ ± z* (SE)where x̄ is the sample mean, z is the z-score corresponding to the desired confidence level, and SE is the standard error.In this case, x̄ = $375, SE = $20, and z = 2.576 (for a 99% confidence level).Therefore, the 99% confidence interval is:$375 ± 2.576 * $20 = $323.40 to $426.60

A Survey of 144 Retail Stores Revealed That the Average