A manufacturer produces light bulbs that have a normally distributed life with a standard deviation of 40 hours. If a sample of 30 bulbs has an average life of 780 a) Find a 96.5% confidence interval for the population mean of all the light bulbs produced by the company. b) How large a sample is required to be if we want to have 90% confidence that the sample mean is within more than 10 hours of the true mean?

A manufacturer produces light bulbs that have a normally distributed life with a standard deviation of 40 hours. If a sample of 30 bulbs has an average life of 780 a) Find a 96.5% confidence interval for the population mean of all the light bulbs produced by the company. b) How large a sample is required to be if we want to have 90% confidence that the sample mean is within more than 10 hours of the true mean?

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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