SOLUTION: A researcher wants to estimate the mean blood cholesterol level of young men ages 15-25 with a 83.27% confidence interval. The blood cholesterol level of young men follows a Normal
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Question 1167441: A researcher wants to estimate the mean blood cholesterol level of young men ages 15-25 with a 83.27% confidence interval. The blood cholesterol level of young men follows a Normal distribution with standard deviation σ = 40 mg/dl. How large a sample would the researcher need to take to estimate the mean blood cholesterol to within 9 mg/dl?
A sample of at least __ people. Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! for z=(+/- 1.38) there is 83.27% of the area.
Look at the table for half the distance between 83.27% and 100% and that is 91.63%. Where the probability is 0.9162 is 1.38
half-interval is 1.38*40/sqrt(n)=9, sigma/sqrt(n)*z=error of measurement
1.38*40/9=sqrt(n)=6.13
n=37.62 or 38, rounding up.
