A phone company has conducted a study of the time its clients spend talking on their cellular phones each day. For a sample of 19 clients the company has obtained a sample standard deviation of 13.3 minutes. We assume that the talk time follows a normal distribution. The confidence interval at the 90% level for the standard deviation of the talk time in the population is: O [10.5, 18.41] O [9.94, 20.62] O [10.3, 19.12] O [9.63, 20.83]

A phone company has conducted a study of the time its clients spend talking on their cellular phones each day. For a sample of 19 clients the company has obtained a sample standard deviation of 13.3 minutes. We assume that the talk time follows a normal distribution. The confidence interval at the 90% level for the standard deviation of the talk time in the population is: O [10.5, 18.41] O [9.94, 20.62] O [10.3, 19.12] O [9.63, 20.83]

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Description: A phone company has conducted a study of the time its clients spend talking on theircellular phones each day. For a sample of 19 clients the company has obtained a samplestandard deviation of 13.3 minutes. We assume that the talk time follows a norm

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

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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