In the manufacturing process of a pharmaceutical product. repeated measurements follow a normal distribution with mean equal to the true product concentration and standard deviation 0.0068 g/l. a.) how many measurements would be needed to estimate the true concentration within ±0.001 g/l with 95% confidence? b.) how many measurements would be needed to estimate the true concentration within ±0.001 g/l with 99% confidence? what is the implication of choosing a higher confidence interval?