A study was conducted to investigate the effectiveness of hypnotism in reducing pain. Results for 8 randomly selected subjects are shown in the data below. Subject: A, B, C, D, E, F, G, H Before: 6.6,...

A study was conducted to investigate the effectiveness of hypnotism in reducing pain. Results for 8 randomly selected subjects are shown in the data below.
Subject: A, B, C, D, E, F, G, H
Before: 6.6, 6.5, 9.0, 10.3, 11.3, 8.1, 6.3, 11.6
After: 6.8, 2.4, 7.4, 8.5, 8.1, 6.1, 3.4, 2.0
A lower score indicates less pain. The "before" value is matched to
an "after" value and the differences are calculated. The differences have a normal distribution. Are the sensory measurements, on average, lower after hypnotism?
Test at a 5% significance level.