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 that the population standard deviation is known to be 2.13, what is the minimum sample size required for the estimate? Round your answer up to the next integer.