we measured braking distances of 13 four cylinder cars and found a mean of 132.5 ft. and a standard deviation of 5.8 feet. For 12 six cylinder cars the mean was 136.3 ft. and the standard deviation was 9.7 feet. Use .05 significance level to test the claim that four cylinder cars have a shorter average braking distance than six cylinder cars. Find the degree of freedom, the critical value, the test statistic, and the p-value.