SOLUTION: a doctor at a local hospital is interested in estimating the birth weight of infants.How large of a sample must she select if she desire to be 98% confident that the mean is within

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Question 865552: a doctor at a local hospital is interested in estimating the birth weight of infants.How large of a sample must she select if she desire to be 98% confident that the mean is within 3 ounces of the sample mean? The standard deviation of the birth weights is known to be 9 ounces.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi
3 = 2.3263%289%2Fsqrt%28n%29%29
n = (2.3263*9/3)^2 = 48.7
n ≥ 49
CI z -value
90% z =1.645
92% z = 1.751
95% z = 1.96
98% z = 2.326
99% z = 2.576