Answer:
(a) The z-critical value for a left-tailed test, for a significance level of α=0.05 is -1.64.
(b) Since -1.54 > -1.64, therefore we accept H₀.
Step-by-step explanation:
(a)
It is given that the value of test statistic is

We need to test the claim that p<0.18.
Null hypothesis: 
Alternative hypothesis: 
It is a left tailed test.
Significance level:

The z-critical value for a left-tailed test, for a significance level of α=0.05 is -1.64.
(b)
It is a left tailed test and critical value is -1.64 it means the region on left of -1.64 is rejection region.
The value of z is -1.54 and the critical value is -1.64.
We know that -1.54 > -1.64.
Therefore we accept H₀.