ANSWER NEEDED PLEASE

Question

Assume that women's heights are normally distributed with a mean given by μ=63.6 in, and a standard deviation given by σ=1.9 in.

(a) If 1 woman is randomly selected, find the probability that her height is less than 64 in.
The probability is approximately ?

(b) If 42 women are randomly selected, find the probability that they have a mean height less than 64 in. The probability is approximately ?

Answer 1

First find z=(x-µ)/σ=(64-63.6)/1.9 and then look up this value in a normal distribution table 

In the second case z=(64-63.6)/(1.9/√42)