Final answer:
Driver error is the single biggest contributor to car crashes.
Step-by-step explanation:
The single biggest contributor to car crashes is driver error.
According to the American Automobile Association, approximately 54 percent of all fatal auto accidents are caused by driver error. In a study of thirty randomly selected fatal accidents, it was determined that 14 were caused by driver error.
Using a significance level of 0.05, we can test the accuracy of the AAA proportion by conducting a hypothesis test.