A survey of 50 retail stores revealed that the average price of a microwave was $375, with a sample standard deviation of $20. If 90% and 95% confidence intervals were developed to estimate the true cost of the microwave, what similarities would they have? Select one: a. Both use the same point estimate of the population mean. b. Both use the same t-statistic. c. Both use the same z-statistic. d. Both have the same confidence level.