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Explanation:
At 95% confidence, the z critical value is roughly z = 1.960
The population standard deviation is given to be sigma = 3.7
The error is E = 2 since we want to be within 2 inches of the population mean mu
The min sample size needed is:
n = (z*sigma/E)^2
n = (1.960*3.7/2)^2
n = 13.147876
n = 14
We always round up to the nearest whole number to ensure that we clear the hurdle (otherwise, the sample is too small). It doesn't matter that we're closer to 13 than to 14.
