An anaesthesiologist made a comparative study of the effects of acupuncture and codeine on postoperative dental pain in male subjects 18 to 30 years old. The four treatments were: (1) placebo treatment-a sugar capsule and two inactive acupuncture points, (2) codeine treatment only{a codeine capsule and two inactive acupuncture points,
(3) acupuncture treatment only-a sugar capsule and two active acupuncture points, and (4) codeine and acupuncture-a codeine capsule and two active acupuncture points. Forty subjects were employed in the study, with 10 assigned randomly to each treatment. Pain intensity indexes were obtained for each subject before the dental treatment and two hours afterwards. Data were collected on a double-blind basis. The change in pain intensity is the response variable of interest. The data on change in pain intensity follow: