Explanation:
H0: p = 0.33
Ha: p
0.33
Sample proportion
= 15 / 96 = 0.15625
Test statistics
z =

=

= -3.62
This is test statistics value.
Critical value at 0.05 level = -1.96 , 1.96.
since test statistics falls in rejection region, we have sufficient evidence to reject H_0.
We conclude at 0.05 level that we have enough evidence to support the claim.