The purpose of an investigation by Morley et al. (A-17) was to evaluate the analgesic effectiveness of a daily dose of oral methadone in patients with chronic neuropathic pain syndromes. The researchers used a visual analogue scale (0–100 mm, higher number indicates higher pain) ratings for maximum pain intensity over the course of the day. Each subject took either 20 mg of methadone or a placebo each day for 5 days. Subjects did not know which treatment they were taking. The following table gives the mean maximum pain intensity scores for the 5 days on methadone and the 5 days on placebo. Do these data provide sufficient evidence, at the .05 level of significance, to indicate that in general the maximum pain intensity is lower on days when methadone is taken?

Subject Methadone Placebo 1 29.8 57.2 2 73.0 69.8 3 98.6 98.2 4 58.8 62.4 5 60.6 67.2 6 57.2 70.6 7 57.2 67.8 8 89.2 95.6 9 97.0 98.4 10 49.8 63.2 11 37.0 63.6 Source: John S. Morley, John Bridson, Tim P. Nash, John B.

Miles, Sarah White, and Matthew K. Makin, “Low-Dose Methadone Has an Analgesic Effect in Neuropathic Pain:

A Double-Blind Randomized Controlled Crossover Trial,”

Palliative Medicine, 17 (2003), 576–587.