A doctor at a local hospital is interested in estimating the

A doctor at a local hospital is interested in estimating the birth weight of infants. How large a sample must she select if she desires to be 98% confident that the true mean is within 2 ounces of the sample mean? The standard deviation of the birth weights is known to be 5 ounces

Solution

marginal error for 98% confidence = 2.3267*5/sqrt(n)

So 2.3267*5/sqrt(n) = 2

n = 33.834 = 34