Question

In a test of braking​ performance, a tire manufacturer measured the stopping distance for one of its tire models. On a test​ track, 10 different cars made stops from a speed of 100 km per hour. The company recorded the stopping distance for each car on both wet and dry pavement. Results are shown in the table. Complete parts​ a) and​ b).

Car #   Dry   Wet
1   48   64
2   44   66
3   41   58
4   40   52
5   42   60
6   40   51
7   42   63
8   37   52
9   41   57
10   46   61

​a) Write a​ 95% confidence interval for the mean dry pavement stopping distance.

The confidence interval is ( _ , _ ).

(Round to one decimal place as​ needed.)

​b) Write a​ 95% confidence interval for the mean increase in stopping distance due to wet pavement.

The confidence interval is ( _ , _ ).

​(Round to one decimal place as​ needed.)

Answer 1