In the results published by Wright et al. (A-2) based on data from the 1999–2000 NHANES study referred to in Exercises 5.4.1 and 5.4.2, investigators reported on their examination of iron levels. The mean iron level for women ages 20–39 years was 13.7 mg with an estimated standard deviation of 8.9 mg. Using these as population values for women ages 20–39, find the probability that a random sample of 100 women will have a mean iron level less than 12 mg.