Question

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 equals 18.4 based on earlier​ studies? Suppose the doctor would be content with 95 % confidence. How does the decrease in confidence affect the sample size​ required?

Answer 1

How does the decrease in confidence affect the sample size​ required

is approximately 141

Step-by-step explanation:

Compute Sample Size

n = (Z a/2 * S.D / ME ) ^2

Zα/2 at 0.01% LOS is = 2.58 ( From Standard Normal Table )

Standard Deviation ( S.D) = 18.4

ME =4

n = ( 2.58*18.4/4) ^2

= (47.472/4 ) ^2

= 140.849 ~ 141