Assume that​ women's heights are normally distributed with a mean given by mu equals 64.5 in​, and a standard deviation given by sigma equals 2.3 in.
​(a) If 1 woman is randomly​ selected, find the probability that her height is less than 65 in.
​(b) If 46 women are randomly​ selected, find the probability that they have a mean height less than 65 in.