A simple random sample of kitchen toasters is to be taken to determine the mean operational lifetime in hours. Assume that the lifetimes are normally distributed with population standard Deviation $\sigma = 21$ hours.
Find the sample size needed so that a 98% confidence interval for the mean lifetime will have a margin Of error of 4.
A) 13
B) 150
C) 3
D) 257

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The Answer of A simple random sample of kitchen toasters is to be taken to determine the mean operational lifetime in hours. Assume that the lifetimes are normally distributed with population standard Deviation $\sigma = 21$ hours.
Find the sample size needed so that a 98% confidence interval for the mean lifetime will have a margin Of error of 4.
A) 13
B) 150
C) 3
D) 257

A Simple Random Sample of Kitchen Toasters Is to Be σ=21\sigma = 21σ=21

A Simple Random Sample of Kitchen Toasters Is to Be $\sigma = 21$