A doctor wants to estimate the mean HDL cholesterol of all20- to29-year-old females. How many subjects are needed to estimate the mean HDL cholesterol within 3 points with 99% confidence assuming s=19.3 based on earlierstudies? Suppose the doctor would be content with 90% confidence. How does the decrease in confidence affect the sample sizerequired?

A 99% confidence level requires

__________subjects.