The print on the package of 100-watt General Electric soft-white light-bulbs says that these bulbs have an average life of 750 hours. Assume that the lives of all such bulbs have a normal distribution with a mean of 750 hours and a standard deviation of 55 hours. Find the probability that the mean life of a random sample of 25 such bulbs will be a. greater than 725 hours. Round your answer to four decimal places. b. between 735 and 745 hours. Round your answer to four decimal places. C. within 5 hours of the population 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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The print on the package of 100-watt General Electric soft-white light-bulbs says that these bulbs have an average life of 750 hours.
Assume that the lives of all such bulbs have a normal distribution with a mean of 750 hours and a standard deviation of 55 hours. Find
the probability that the mean life of a random sample of 25 such bulbs will be
a. greater than 725 hours.
Round your answer to four decimal places.
b. between 735 and 745 hours.
Round your answer to four decimal places.
c. within 5 hours of the population mean.
Round your answer to four decimal places.
d. less than the population mean by at least 20 hours or more.
Round your answer to four decimal places.
Transcribed Image Text:The print on the package of 100-watt General Electric soft-white light-bulbs says that these bulbs have an average life of 750 hours. Assume that the lives of all such bulbs have a normal distribution with a mean of 750 hours and a standard deviation of 55 hours. Find the probability that the mean life of a random sample of 25 such bulbs will be a. greater than 725 hours. Round your answer to four decimal places. b. between 735 and 745 hours. Round your answer to four decimal places. c. within 5 hours of the population mean. Round your answer to four decimal places. d. less than the population mean by at least 20 hours or more. Round your answer to four decimal places.
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