A survey of 34 randomly selected iPhone owners showed that the purchase price has a mean of $640 with a sample standard deviation of $40. (Uset Distribution Table & z Distribution Table.) Required: a. What is the point estimate of the population mean?

b. What is the point estimate of the population standard deviation? c. What is the standard error of the sample mean? (Round your answers to the nearest whole number.) d. Compute the 90% confidence interval to estimate the population mean. (Round your answers to 3 decimal places.) e.How many users need to be sampled to estimate the population mean price with 90% confidence and a $12 margin of error? (Round up your answer to the next whole number.)