A 2011 article published in the Journal of Substance Abuse Treatment reports the results of a randomized clinical trial designed to assess the effects of acupuncture on anxiety related to withdrawal from psychoactive drugs. As per the abstract: (you may recall this article from Homework 1 of Statistical Concepts 1 "Auricular acupuncture (AA) is a widely accepted treatment option for substance abuse that is used in more than 700 treatment centers worldwide. Despite claims of perceived clinical benefits by patients and treatment staff, research efforts have failed to substantiate purported benefits, and the mechanism(s) by which AA serves in the treatment of addiction remain inconclusive. Numerous studies have shown AA to be an effective treatment for perioperative anxiety. In this study, we hypothesize that AA reduces the anxiety associated with withdrawal from psychoactive drugs. The study used a randomized, controlled design and included a sample of 101 patients recruited from an addiction treatment service. Subjects were assigned to one of three treatment groups (National Acupuncture Detoxification Association [NADA] AA, AA at sham points, or treatment setting control) and were instructed to attend treatment sessions for 3 days. The primary outcome measure state anxiety was assessed using a pretest- posttest treatment design."The following boxplots (Figure 4 in the article) show the main results from this study: (higher anxiety scores indicate higher anxiety)NADA Sham Relaxation 2 2 State Anxiety score State Anxiety score State Anxiety score Before Session Alter Session Before Session After Session Belore Session After Session Enasian Timrien Comeinn Timing Caninn Timing The boxplots show the unadjusted comparisons of the anxiety score distributions before and after the treatment sessions for each of the 3 treatments. The authors do not provide any adjusted comparisons in the manuscript. Is this appropriate, or did they blatantly ignore a high potential for confounding? a. Because this study is an observational study, these results are likely to be confounded by other participant characteristics. b. Because this study is an observational study, these results are not likely to be confounded by other participant characteristics. c. Because this study is an randomized trial, these results are likely to be confounded by other participant characteristics. d. Because this study is an randomized trial, these results are not likely to be confounded by other participant characteristics