Since muscle tension in the head region has been associated with tension headaches, you reason that if the muscle tension could be reduced, perhaps the headaches would decrease or go away altogether....

Since muscle tension in the head region has been associated with tension headaches, you reason that if the muscle tension could be reduced, perhaps the headaches would decrease or go away altogether. You design an experiment in which nine subjects with tension headaches participate. The subjects keep daily logs of the number of headaches they experience during a 2-week baseline period. Then you train them to lower their muscle tension in the head region, using a biofeedback device. For this experiment, the biofeedback device is connected to the frontals muscle, a muscle in the forehead region. The device tells the subject the amount of tension in the muscle to which it is attached (in this case, frontals) and helps them achieve low tension levels. After 6 weeks of training, during which the subjects have become successful at maintaining low frontals muscle tension, they again keep a 2-week log of the number of headaches experienced. The following are the numbers of headaches recorded during each 2-week period.

a. Using??
= 0.052 tail, what do you conclude?

Assume the sampling distribution of the mean of the difference scores is normally distributed.

Assume a no directional hypothesis is appropriate, because there is insufficient empirical basis to warrant a directional hypothesis.

b. If the sampling distribution of is not normally distributed, what other test could you use to analyze the data? What would your conclusion be?