The waist measurements of a population of adult females is normal with a mean of 38.7 inches, with a standard deviation of 3.5 inches. Assume that waist measurement is independent and follows a Normal model.

a) If another group of women with an average waist measurement of 36.6 inches and a standard deviation of 2.78 inches is added in that population, what is the expected value and standard deviation of the total waist measurements for the new population?

b) What is the probability that the women of the new population will have waist measurements of more than 70 inches?