A simple random sample of 50 speeds (in mph) is obtained from cars traveling on a section of I-10 through Tallahassee. The sample has a mean of 72.3 mph and a standard deviation of 7.4 mph. Use a 0.05 significance level to test the claim that the mean speed of all cars is greater than the posted speed limit of 70 mph. Based on the above situation compute the value of the test statistic