A survey of eight vice presidents of information technology and information systems, who had been in their current positions for 10 years or less, revealed $174,813 as the average salary.15 Assume a random sample with a standard deviation of $25,000.
a. Find the 95% confidence interval for the population mean salary.
b. Find the 99% confidence interval for the population mean salary.
c. Complete the following sentence: We are 95% sure that the population mean salary is at least ______________________.