Answer:
(a) The critical value is -1.64.
(b) We fail to reject the null hypothesis H₀.
Step-by-step explanation:
(a)
The test statistic of z=-2.01 is obtained when testing the claim that p<0.18. It means the data belongs to normal distribution.
Null hypothesis:
[tex]H_0:p\geq 0.18[/tex]
Alternative hypothesis:
[tex]H_1:p<0.18[/tex]
It is left tailed test.
Using a significance level of α=0.05 we need to find the critical value.
From the standard normal table the critical value at α=0.05 for left tailed is -1.64.
Therefore the critical value is -1.64.
(b)
If z > critical value, then we reject the null hypothesis.
If z < critical value, then we fail to reject the null hypothesis.
In the given problem z=-2.01 and critical value = -1.64.
[tex]-2.01<-1.64\Rightarrow z<\text{critical value}[/tex]
Since z < critical value, therefore we fail to reject the null hypothesis H₀.