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A simple random sample of electronic components will be selected to test for the mean lifetime...

A simple random sample of electronic components will be selected to test for the mean lifetime in hours. Assume that component lifetimes are normally distributed with population standard deviation of 31 hours. How many components must be sampled so that a 99% confidence interval will have margin of error of 6 hours?

Write only an integer as your answer.
Math   Statistics-And-Probability   
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Answer #1

Refer Standard normal table/Z-table or use excel function "=NORM.S.INV((1-0.005))" to find the Z-value.

Round the value to the nearest integer.

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