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.

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Treatment Treatment Treatment 90 74 90 86 75 81 90 90 90 85 3 20 12