Assume we draw a simple random sample from a population having a mean of 100 and a standard deviation of 16. What is the probability that a sample mean will be within plus-or-minus two of the population mean for each of the following sample sizes?
(a) n = 50 ____________
(b) n = 100 ____________
(c) n = 200 ____________
(d) n = 400 ____________