A researcher would like to determine if a specific breathing training will reduce the number of asthma attacks for chronic sufferers. For a week prior to the training, each subject records the number of attacks. Subjects then receive training and, for the week following, the number of attacks is again measured. The change (differences) in number of attacks before and after training is as follows (minus signs indicate a reduction so watch if this is one-tail or two-tail in set up):
-1, -3, 0, -4, -3, +2, -7
Is there an effect in training? Use alpha=.05.
1. What critical value of t is associated with this alpha level? Please explain.