(Solved): Adolescent Obesity. Adolescent obesity is a serious health risk affecting more than 5 million young ...

Adolescent Obesity. Adolescent obesity is a serious health risk affecting more than 5 million young people in the United States alone. Laparoscopic adjustable gastric banding has the potential to provide a safe and effective treatment. Fifty adolescents between 14 and 18 years old with a body mass index (BMI) higher than 35 were recruited from the Melbourne, Australia, com- munity for the study. ^(20) Twenty-five were randomly se- lected to undergo gastric banding, and the remaining 25 were assigned to a supervised lifestyle intervention program involving diet, exercise, and behavior modifi- cation. All subjects were followed for two years. Here are the weight losses, in kilograms, for the subjects who completed the study: (a) In the context of this study, what do the negative values in the data set mean? (b) Give a graphical comparison of the weight loss distributions for the two groups, using side-by-side boxplots. Provide appropriate numerical summaries for the two distributions and identify any high outliers in either group. What can you say about the effects of gastric banding versus lifestyle intervention on weight loss for the subjects in this study? (c) The measured variable was weight loss, in kilograms. Would two subjects with the same weight loss always have similar benefits from a weight-reduction program? Does it depend on their initial weights? Other variables considered in this study were the percentage of excess weight lost and the reduction in BMI. Do you see any advantages to either of these variables when comparing weight loss for two groups? (d) One subject from the gastric-banding group dropped out of the study, and seven subjects from the lifestyle group dropped out. Of the seven dropouts in the lifestyle group, six had gained weight at the time they dropped out. If all subjects had completed the study, how do you think it would have affected the comparison between the two groups?