February 18th, 2020
A doctor wants to estimate the HDL cholesterol of all 20-29-year-old females. How many subjects are needed to estimate the HD cholesterol within 4 points with 99% confidence assuming the Q = 17.9? Suppose the Doctor would be content with 95% confidence.
How does the decrease in confidence affect the sample size required?A 99% confidence level requires (?) subjects.Because a 95% confidence interval is required .04 points. Use a standard normal table to find the critical value. (?)
ME= 4STD DEV = 17.97Z VALUE = 2.576 for 99%SO n = [ z*17.97/4]^2 = 133.899=139If we now want 95% then z= 1.96N= [1.96*17.97 /4 ]^2 = 77.533 = 78Higher is confidence wider is the margin of error