SOLUTION: a sample of 29 federally sentenced adult male prisoners had an average sentence of 9 years. population standard deviation of a sentence length is 17 years. compute a 90% confidence

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Question 1012916: a sample of 29 federally sentenced adult male prisoners had an average sentence of 9 years. population standard deviation of a sentence length is 17 years. compute a 90% confidence interval for the mean sentence length.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
90%CI has an interval of
1.645(s/sqrt (n))
1.645(17/sqrt (29))
=5.19 years
So the 90% CI is 9+/- 5.17
(3.83,14.17)
Use the z-value because not estimating the population sd from the sample but know it from pop.