Answer:
a) -1.25
b) 0.2112
c) -1.96
Step-by-step explanation:
Data provided in the question:
Sample size, n = 400
H0 : p = 20
= 175
Now,
a) The test statistic is given as:
Z =
on substituting the respective values, we get
Z =
= -1.25
b) The p-value = 2 × P(Z <-1.25)
Now from the standard normal table
P(Z <-1.25) = 10.56% = 0.1056
Thus,
p-value = 2 × 1056 = 0.2112
c) for a = 0.05,
the critical value is i.e
Now from standard normal table
= -1.96