Question

9.2.41 Question Help A doctor wants to estimate the mean HDL cholesterol of all 20-to 29-year-old females. How many subjects are needed to estimati the mean HDL cholesterol within 3 points with 99% confidence assuming s = 13.3 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 131 subjects. (Round up to the nearest subject.) A 95% confidence level requires subjects. (Round up to the nearest subject.) Enter your answer in the answer box and then click Check Answer. part remaining Clear All Check Answer

Answer 1

Solu> Griven a Standard deviation (S) = 1363 Margin of error (E) =_3 - At 99% Confidence level Q=-0.991 = 0.01 2/2 = 0.0172 = 0.005 Z2/2 = 2.58 then, Sample size (n) = (2412*). - E 2.58 * 13.3 (2-5€ *12:3) - (H-43815 = 130.827844 n = 131_ lapperoximately 9544. confidence level 2 = (1-0.95) =0.05 2/2 = 0.05% = 0.025 Zx/2 =1.96 To97 303 Sample size(n).: ( _ =18.6912 ne 75.5161 me 76 t Ahhroximately)