The lifetime of a certain brand of battery is known to have a standard deviation of 9 hours. Suppose that a random sample of 80 such batteries has a mean lifetime of 37.7 hours. Based on this sample, find a 90% confidence interval for the true mean lifetime of all batteries of this brand. Then give its lower limit and upper limit. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit: | Upper limit:

A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
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Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
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The lifetime of a certain brand of battery is known to have a standard deviation of 9 hours. Suppose that a random sample of 80 such batteries has a mean
lifetime of 37.7 hours. Based on this sample, find a 90% confidence interval for the true mean lifetime of all batteries of this brand. Then give its lower limit and
upper limit.
Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.)
Lower limit: |
Upper limit:
Transcribed Image Text:The lifetime of a certain brand of battery is known to have a standard deviation of 9 hours. Suppose that a random sample of 80 such batteries has a mean lifetime of 37.7 hours. Based on this sample, find a 90% confidence interval for the true mean lifetime of all batteries of this brand. Then give its lower limit and upper limit. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit: | Upper limit:
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