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= 14.7 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. subjects. (Round up to the nearest subject.) subjects. (Round up to the nearest subject.) A 99% confidence level requires A 95% confidence level requires How does the decrease in confidence affect the sample size required? O A. Decreasing the confidence level increases the sample size needed. OB. The sample size is the same for all levels of confidence OC. Decreasing the confidence level decreases the sample size needed. Partial Critical Value Table Level of Confidence, (1-x) 100% 90% 95% 99% Area in Each Tail, Print 0.05 0.025 0.005 α 2 Dono Critical Value, Za/2 1.645 1.96 2575

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