Suppose that the life expectancy of a certain brand of nondefective light bulbs is normally​ distributed, with a mean life of 1400 hr and a standard deviation of 100 hr. If 90,000 of these bulbs are​ produced, how many will last between 1830hr and 1975 ​hr?   The number of light bulbs that will last between 1290 hr and 1540 hr is ??

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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Suppose that the life expectancy of a certain brand of nondefective light bulbs is normally​ distributed, with a mean life of 1400 hr and a standard deviation of 100 hr. If 90,000 of these bulbs are​ produced, how many will last between 1830hr and 1975 ​hr?

 

The number of light bulbs that will last between 1290 hr and 1540 hr is ??

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