To test the durability of the material used for running shoes, a sample is placed in testing device that simulates an average-sized person using the shoes until the material wears out. The material is supposed to last at least an average of 20 months. Suppose that the wear-out time is characterized by a normal distribution with both μ and σ unknown. A test on five ra

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.5: Comparing Sets Of Data
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To test the durability of the material used for running shoes, a sample is placed in testing device that simulates an average-sized person using the shoes until the material wears out. The material is supposed to last at least an average of 20 months. Suppose that the wear-out time is characterized by a normal distribution with both μ and σ unknown.

A test on five randomly selected pairs of shoes yields wear-out times of 20, 28, 18, 24, and 25 months.

a) If the mean shoe wear-out time of the sample is is 22 months, or stated differently, what is the power for μa = 22?

b) What sample size (n) is needed to achieve β = 0.1 for μa = 22 months?

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