A research scholar wants to know how many times per hour a certain strand of virus reproduces. He wants to construct the 80% confidence interval with a maximum error of 0.15 reproductions per hour....

A research scholar wants to know how many times per hour a certain strand of virus reproduces. He wants to construct the 80% confidence interval with a maximum error of 0.15 reproductions per hour. Assuming the population standard deviation is known to be 2.13, what is the minimum sample size required for the estimate?