Answer:
The proportion is less than 0.75 only
Step-by-step explanation:
given that the ability of auto mechanics to identify simple engine problems, an automobile with a single suchproblem was taken to 72 different car repair facilities.
Sample proportion
Set up hypotheses as
H0: p =0.75
Ha: p < 0.75
(Left tailed test)
Assuming H0 to be true, std error of proportion =
p difference = -0.1667
Test statistic Z = p diff/std error = -2.50
p value = 0.0062
since p is less than0.05 at 5% significance level we reject null hypothesis
The proportion is less than 0.75 only