An article in the journal Applied Nutritional Investigation reported the results of a comparison of a low-calorie soy-protein diet and a low-calorie traditional-protein diet (Liao, 2007). Twelve obese participants were randomly assigned to each diet. At the end of the diet period, those on the soy diet lost on average 2.3 percent of their body fat (SD = 0.55), while those on the traditional diet lost an average of 1.22 percent of their body fat (SD = 0.50). Calculate and interpret the appropriate effect size for this study.