An electrical firm manufactures light bulbs that have a length life with normal distribution, and a standard deviation of o= 10 hours. A sample of size n = 100 is obtained, and its sample mean is calculated to be = 400 hours. Find the 99% confidence interval for the average length life fl. Find the upper 99% bound for the average length life μ. Find the lower 99% bound for the average length life μl.

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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An electrical firm manufactures light bulbs that have a
length life with normal distribution, and a standard
deviation of o 10 hours. A sample of size n 100 is
obtained, and its sample mean is calculated to be = 400
hours.
=
Find the 99% confidence interval for the average length life
μl.
=
Find the upper 99% bound for the average length life .
Find the lower 99% bound for the average length life .
Give your answer as intervals. Use
—
-∞ and +∞ if needed.
Transcribed Image Text:An electrical firm manufactures light bulbs that have a length life with normal distribution, and a standard deviation of o 10 hours. A sample of size n 100 is obtained, and its sample mean is calculated to be = 400 hours. = Find the 99% confidence interval for the average length life μl. = Find the upper 99% bound for the average length life . Find the lower 99% bound for the average length life . Give your answer as intervals. Use — -∞ and +∞ if needed.
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