SOLUTION: In a hospital study, the mean noise level in the 171 ward areas was 58.0 decibels, and the Population standard deviation is 4.8. Find the 90% confidence interval of the true mean.

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Question 1193228: In a hospital study, the mean noise level in the 171 ward areas was 58.0 decibels, and the Population standard deviation is 4.8. Find the 90% confidence interval of the true mean.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
90% half-interval is z*sigma/sqrt(n)
=1.645*4.8/sqrt(171)
=0.60
(57.4, 58.6) decibels