The average life of a bread-making machine is 7 years, with a standard deviation of 1 year. If the lives of these machines follow approximately a normal distribution, find the probability that the mean life of a random sample of 9 such machines fall between 6.4 and 7.2 years. A) 0.7845 0.6898 0.5445 0.4889

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
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ISBN:9780079039897
Author:Carter
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Chapter10: Statistics
Section10.5: Comparing Sets Of Data
Problem 4CYU
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The average life of a bread-making machine is 7 years, with a standard deviation of 1 year. If the lives of these machines follow
approximately a normal distribution, find the probability that the mean life of a random sample of 9 such machines fall between 6.4
and 7.2 years.
A) 0.7845
B) 0.6898
0.5445
0.4889
Transcribed Image Text:The average life of a bread-making machine is 7 years, with a standard deviation of 1 year. If the lives of these machines follow approximately a normal distribution, find the probability that the mean life of a random sample of 9 such machines fall between 6.4 and 7.2 years. A) 0.7845 B) 0.6898 0.5445 0.4889
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