A treatment for fatigue was administered to two groups of patients, where one group called treatment consisting of 12 patients received the treatment and another group called control consisting of 12 patients who were on the waiting list did not receive the treatment. Fatigue was rated on a scale of 1 = 'hardly any fatigue' through to 7 = 'severe fatigue'. The data of the fatigue score for the 24 patients are shown in the following table. Treatment Control Group 1 Group 2 Sample Size Mean Rank Sum of Ranks