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13 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 4 points with 99% confidence assuming s = 17 2 based on earlier studies? Suppose the doctor would be content with 95% 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.) A95% confidence level requires | | subjects. (Round up to the nearest subject.) How does the decrease in confidence affect the sample size required? O A. The sample size is the same for all levels of confidence. O B. Decreasing the confidence level decreases the sample size needed. O C. Decreasing the confidence level increases the sample size needed. i Partial Critical Value Table - X Level of Confidence, (1- () . 100% Area in Each Tail, Critical Value, Za/2 90% 0.05 1.64 95% 0.025 1.96 99% 0.005 2.575 Print Done Construct a 99% confidence interval of the population proportion using the given information. * = 120, n =200 Click here to view the table of critical values. The lower bound is The upper bound is (Round to three decimal places as needed.) i Table of critical values - X Level of Confidence, (1 - a) - 100% Area in Each Tail, 7 Critical Value, #7 90% 0.05 1.645 95% 196 99%% 0.003 2 575 Print Done