The ages of a group of 131 randomly selected adult females have a standard deviation of 18.9 years. Assume that the ages of female statistics students have less variation than ages of females in the general? population, so let sigmaσ=18.9 years for the sample size calculation. How many female statistics student ages must be obtained in order to estimate the mean age of all female statistics? students? Assume that we want 95?% confidence that the sample mean is within? one-half year of the population mean. Does it seem reasonable to assume that the ages of female statistics students have less variation than ages of females in the general? population?