A doctor wants to estimate the mean HDL cholesterol of all​ 20- to​ 29-year-old females. How many subjects are needed to estimate the mean HDL cholesterol within 2 points with 99% confidence assuming...

A doctor wants to estimate the mean HDL cholesterol of all​ 20- to​ 29-year-old females. How many subjects are needed to estimate the mean HDL cholesterol within

points with

confidence assuming

based on earlier​ studies? Suppose the doctor would be content with

confidence. How does the decrease in confidence affect the sample size​ required?

Click the icon to view a partial table of critical values.

A​ 99% confidence level requires

subjects. ​(Round up to the nearest​ subject.)