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 3 points with 99% confidence assuming s = 19.5 based on earlier studies? Suppose the doctor would be content with 90% confidence. How does the decrease in confidence affect the sample size required? Click the icon to view a partial table of critical values. X Partial critical value table A 99% confidence level requires subjects. (Round up to the ne Level of Confidence, Critical Value, Zx / 2 (1 -a) . 100% Area in Each Tail, 2 90% 0.05 1.645 95% 0.025 1.96 99% 0.005 2.575 Help me solve this View an example Get swer Print Done