Question: (a) Suppose a study of blood concentration of a certain protein is being done. Groups of 350 patients are sampled. It is known from parallel studies that σ = 1.04, and the sample means are x¯ = 72. For a 99% confidence level, estimate the population mean and the confidence interval.
(b) Suppose in (a), the sample size has not yet been determined, but n should be chosen to have a 99% confidence level and an error of no more than 0.2. Estimate the sample size that should be used.