Question: In an experiment designed to study the effects of illumination level on task performance, subjects were required to insert a fine-tipped probe into the eyeholes of ten needles in rapid succession both for a low light level with a black background & again at a higher light level with a white background. Each data value is the time [in seconds] to complete the task.
|
Subject
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
|
Black
|
28.85
|
28.84
|
32.05
|
25.74
|
20.89
|
41.05
|
25.01
|
24.96
|
27.47
|
|
White
|
18.23
|
20.84
|
22.96
|
19.68
|
19.50
|
24.98
|
16.61
|
16.07
|
24.59
|
Does the data indicate at the 0.02 level that the higher level of illumination with a white background yields a decrease of more than five seconds in the true mean completion time of the task?