Researchers conducting a clinicaltrial randomly assigned 60 patients with painful kneeosteoarthritis evenly into one of three treatment groups:glucosamine, chondroitin, or placebo.After the study period,patients were asked if they experienced substantial improvement inpain and ability to function normally.Thirty-four patients repliedthat they did have an improvement, including 13 in the glucosaminegroup, 16 in the chondroitin group, and 5 in the placebo group.
List a potential confounding variablefor this study and briefly explain a possible consequence it couldhave on the results.
