Rockwell hardness of pins of a certain type is known to have a mean value of 50

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Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.2.

a. If the distribution is normal, what is the probability that the sample mean hardness for a random sample of 9 pins is at least 51?

b. What is the (approximate) probability that the sample mean hardness for a random sample of 40 pins is at least 51?

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Probability And Statistics For Engineering And The Sciences

ISBN: 9781111802325

7th Edition

Authors: Dave Ellis, Jay L Devore

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Question Posted: Sep 16, 2024 09:00 AM

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Rockwell hardness of pins of a certain type is known to have a mean value of 50

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Probability And Statistics For Engineering And The Sciences

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