02:20
Intro Stats / AP Statistics
An obstacle course was set up on a campus,
and 12 volunteers were given a chance to complete it
while they were being timed. They then sampled a new energy drink
and were given the opportunity to run the course again. The
"before" and "after" times in seconds are shown below. Is there
sufficient evidence at a=0.05 to conclude that the
students did better the second time? Assume the variables are
normally distributed.
Student
1
2
3
4
5
6
7
8
9
10
11
12
Before
70
78
82
75
69
68
76
76
77
67
72
80
After
65
75
78
68
65
70
73
76
73
68
70
76