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Homework Statement
Glucose level is normally distributed, standard deviation is known to be 25 units; determine the sample size needed to be 95% confident that the sample mean and the true population mean differ by at most 4 units.
Homework Equations
(work shown below)
The Attempt at a Solution
Margin of error = 4 units
Margin of error = z * standard error
4=1.96 * (25/(n)^1/2)
4 = (49) / (n)^1/2
49 = 4(n)^1/2
(12.25)^2 = (n^1/2)^2
n=151