SOLUTION: SAT scores are normally distributed with a mean of 1,500 and a standard deviation of 300. An administrator at a college is interested in estimating the average SAT score of first-y

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Question 1156422: SAT scores are normally distributed with a mean of 1,500 and a standard deviation of 300. An administrator at a college is interested in estimating the average SAT score of first-year students. If the administrator would like to limit the margin of error of the 88% confidence interval to 20 points, how many students should the administrator sample? Make sure to give a whole number answer.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
use z since sd known
error is +/-z 0.94*sigma/sqrt(n)=20
1.55*300/sqrt(n)=20
square both sides
216225/n=400
n=540.56 or 541