A standard method for the determination of glucose in serum is reported to have a standard deviation of 0.36 mg/dL. If s = 0.36 is a good estimate of σ, how many replicate determinations should be made in order for the mean for the analysis of a sample to be within
(a) 0.3 mg/dL of the true mean 99% of the time?
(b) 0.3 mg/dL of the true mean 95% of the time?
(c) 0.3 mg/dL of the true mean 90% of the time?