To illustrate the effects of driving under the influence of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine teenagers, the time (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded.

Data:

Subject Normal, Xi Impaired, Yi

1 4.49 5.77

2 4.34 5.85

3 4.585.51

44.65 5.29

5 4.31 5.90

6 4.80 5.49

7 4.555.23

8 5.00 5.63

9 4.79 5.63

(A) Make a 95% confidence interval

(B) Why is this a good idea in designing the experiment?

(C) State the appropriate conclusion