Answer:
a) Mean = 19
b) Standard Deviation = 3.08
Explanation:
This is binomial probability distribution. We need to find the mean and standard deviation.
a) Mean
The formula for mean is:

Where n is the number of people, which is 38 and p is the probability of girl, which is 0.5
n = 38
p = 0.5
So,

Mean = 19
b) Standard Deviation
Standard deviation has the formula:

Where n and p are the same variables in part (a)
So we plug them in and find:

Standard Deviation = 3.08