An allergy specialist wishes to test a randomly selected sample of n patients to estimate the mean sinus pressure, in psi (pounds per square inch), of all American allergy sufferers. The doctor wants a 99% confidence interval estimate with a bound on the error of 2 psi. He also knows that the pressures only range from 5 psi to 25 psi. How large of a sample should be used? (HINT: Use the range estimate of standard deviation.)

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