(1 point) the epa wants to test a randomly selected sample of n water specimens and estimate the mean daily rate of pollution produced by a mining operation. if the epa wants a 90% confidence interval with a bound of error of 0.5 milligram per liter (mg/l), how many water specimens are required in the sample? assume prior knowledge indicates that pollution readings in water samples taken during a day have been approximately normally distributed with a standard deviation of 5.4 (mg/l).