A doctor wants to estimate the HDL cholesterol of all 20- to 29-year-old females. How many subjects are needed to estimate the HDL cholesterol within 2 points with 99 % confidence assuming sigma= 15.6? Suppose the doctor would be content with 90 % confidence. How does the decrease in confidence affect the sample size required?

a)A 99% confidence level requires [ ??] Subjects

b)A 90 % confidence level requires [??] Subjects

2)How does the decrease in confidence affect the sample size required?

a)The lower the confidence level the larger the sample size.

b)The sample size is the same for all levels of confidence.

c)The lower the confidence level the smaller the sample size.