he mere belief that you are receiving an effective treatment for pain can reduce the pain you actually feel. Researchers tested this placebo effect on 37 volunteers. Each volunteer was put inside a magnetic resonance imaging​ (MRI) machine for two consecutive sessions. During the first​ session, electric shocks were applied to their arms and the blood oxygen​ level-dependent (BOLD) signal was recorded during pain. The second session was the same as the​ first, but prior to applying the electric​ shocks, the researchers smeared a cream on the​ volunteer's arms. The volunteers were informed that the cream would block the pain​ when, in​ fact, it was just a regular skin lotion​ (i.e., a​ placebo). Note that each participant is contributing a pair of data: one measurement in the first session, and one measurement in the second session. From the 37 participants, the mean and standard deviation of differences in BOLD measurements are calculated. If the placebo is effective in reducing the pain​ experience, the BOLD measurements should be​ higher, on​ average, in the first MRI session than in the second. Is there evidence to confirm that the placebo is effective? That is, that the mean BOLD measurements are higher in the first session than the second? Test at LaTeX: \alphaα=.05.