Use the data of Exercise 19 to calculate a 95% CI for the difference between true average stopping distance for cars equipped with system 1 and cars equipped with system 2. Does the interval suggest that precise information about the value of this difference is available?
Data From Exercise 19
Suppose µ1 and µ2 are true mean stopping distances at 50 mph for cars of a certain type equipped with two different types of braking systems. Use the two-sample t test at significance level .01 to test H0: µ1 - µ2 < -10 versus Ha: µ1 - µ2 < -10 for the following data:
M = 6 ,  = 115.7, s1 = 5.03, n = 6,  = 129.3, and s2 = 5.38.