We want to know whether an independent variable (room temperature) affects scores on a dependent variable (ratings of anger). The levels of the IV are hot and cold and the DV is measured on an anger scale (ranging from 0 no anger to 10 high anger). A random sample of subjects has been taken from the universe. Half of the subjects are randomly placed in the hot room while the other half are placed in the cold room.
The samples are said to be because subjects are responding in the hot room than are responding in the cold room.

The data: Subject Hot room Subject Cold room
1 5 11 3
2 8 12 2
3 5 13 6
4 8 14 6
5 9 15 4
6 7 16 4
7 2 17 3
8 8 18 2
9 4 19 2
10 6 20 3

Use  = .05 to test the hypothesis that room temperature will influence anger ratings.