A safety officer wants to prove that ? = the average speed of cars driven by a school is less than 27.2 mph. Suppose that a random sample of 20 cars shows an average speed of 26.0 mph, with a sample standard deviation of 2.5 mph. Assume that the speeds of cars are normally distributed. A. What are the appropriate null and alternative hypotheses? B. What is the value of the test statistic? C. What is the p-value? D. For a significance level of a= 0.05, are the results statistically significant? E. What is an appropriate conclusion