1.For the population of females between the ages of 3 and 74 who participated in the National Health Interview Survey, the hemoglobin level is approximately normally distributed with mean 13.3g/100ml and standard deviation 1.12g/100ml.

a.If a sample of size 15 is selected from this population, what is the probability that the mean hemoglobin level of the sample is between 13.0g/100ml and 13.6g/100ml?

b.If a sample of size 30 is selected from this population, what is the probability that the mean hemoglobin level of the sample is between 13.0g/100ml and 13.6g/100ml?

c.How large must the sample be so that the probability that the mean hemoglobin level of the sample is within +/- 0.2g/100ml of the population mean is 95%?