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. (?)