Conduct a multiple comparison of means by Tukey’s method to determine exactly where the significant differences occur in Problem 26.

Data From Problem 26

Psychologists studied the relative efficacy of three different treatment programs—A, B,  and C—on illicit drug abuse. The following data represent the number of days of drug abstinence  accumulated by 15 patients (5 in each treatment program) for the 3 months after  their treatment program ended. Thus, a larger number of days indicates a longer period free  of drug use.

Test the null hypothesis that these drug-treatment programs do not differ in regard to their efficacy.

Transcribed Image Text:

Treatment A 90 74 90 86 75 Treatment B 81 90 90 90 85 Treatment C 14 20 33 5 12