A sociologist claimed that the number of girls in families with four kids has a binomial

A sociologist claimed that the number of girls in families with four kids has a binomial distribution with n=4 and success probability =0.5. Her 40 students went out in their respective neighborhoods, identified families with four kids and recorded the number of girls in those families. The data is summarized below.

# Girls

0

1

2

3

4

Total

# Families

8

46

115

112

39

320

a) Conduct a test for H0: =0.5 against the two-sided alternative using Wald test. Report P-value. 

b) Construct a 90% Wald confidence interval for .