K 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 16 1 based on earlier studies Suppose the doctor would be content with 90 confidence How does the decrease in confider 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 Partial Critical Value Table Level of Confidence 1 x 100 90 95 FRISSEN Area in Each Tail 0 05 0 025 XX 2 Critical Value Z 2 1 645 196 X U