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Sample size

A previous study of nickels showed that the standard deviation of the weight of nickels is 250 miligrams. A coin counter manufacturer wishes to find the 90% confidence interval for the average weight of a nickel. How many nickels does he need to weigh to be accurate within 15 miligrams?

a. 457
b. 278
c. 752
d. 1068

Solution Summary

This solution gives the step by step method for computing sample size .