Answer: p-value of the test = 0.167
Step-by-step explanation:
Given that,
sample size n = 400
sample success X = 80
confidence = 95%
significance level = 1 - (95/100) = 0.05
This is the left tailed test .
The null and alternative hypothesis is
H₀ : p = 0.22
Hₐ : p < 0.22
P = x/n = 80/400 = 0.2
Standard deviation of proportion α = √{ (p ( 1 - p ) / n }
α = √ { ( 0.22 ( 1 - 0.22 ) / 400 }
α = √ { 0.1716 / 400 }
α = √0.000429
α = 0.0207
Test statistic
z = (p - p₀) / α
z = ( 0.2 - 0.22 ) / 0.0207
z = - 0.02 / 0.0207
z = - 0.9661
fail to reject null hypothesis.
P-value Approach
P-value = 0.167
As P-value >= 0.05, fail to reject null hypothesis.
Since test is left tailed so p-value of the test is 0.167. Since p-value is greater than 0.05 so we fail to reject the null hypothesis.
