A researcher would like to find out if relaxation training will affect number of headaches for chronic headache sufferers. For a week prior to training, each participant records the number of headaches suffered. Participants then receive relaxation training and for the week following training the number of headaches is again measured. The data are as follows:
Before After
6 4
5 1
3 3
3 1
6 2
2 1
4 3
4 2