Question

A group of 268 overweight people signed up for a weight loss program. Participants were asked to choose whether they wanted to go on a vegetarian diet or follow a traditional low-calorie diet that included some meat. 153 people chose the vegetarian diet, and the rest chose to be in the control group and continue to eat meat. There was a greater weight loss in the vegetarian group.

1. What is the sample size of each group? What percentage of people was in the vegetarian group? What percentage was in the meat group? (Round to the nearest percent.)
2. What are the variables in this study? Remember that variables are used to record the characteristics of individual people or things. The description above does not necessarily name all the variables - you have to make an educated guess about what characteristics were measured and recorded in order to conduct this study. For each variable, indicate whether it is a categorical variable or a numerical variable, and explain why.
3. What confounding variables might account for the increased weight loss in the vegetarian group? Explain.
4. an observational or a controlled study?
5. should I design the study that is more likely to remove the effect of confounding variables

Answer 1

(a)

Sample Size of Vegetarian diet Group = 153

Sample Size of Control Group : Traditional low-calorie diet that included some meat. = 268 - 153 = 115

Percentage of people in Vegetarian diet Group = (153/268) X 100 = 57.09 %

Percentage of people in Control Group : Traditional low-calorie diet that included some meat. = (115/268) X 100 = 42.91%

(b)
Variable 1: Weight loss - numerical variable, because weight loss is a measurable quantity

Variable 2: Diet - Categorical variable, because the vaue of Diet is either Vegetarian or Traditional low-calorie diet that included some meat.

(c)

Confounding variables might account for the increased weight loss in the vegetarian group: (i) Inherent characteristic of in individual to have weight loss irrespective of type of diet (ii) Factors other than diet which can cause weight loss: cancer, depression, bowl diseases etc.

(d) This is a controlled study, because the experiment has two basic elements: control group and treatment group.

(e) To remove the effect of confounding variables, the volunteers for this experimentation should have the same oss in the vegetarian group: (i) Inherent characteristic of in individual to have weight loss irrespective of type of diet and they should not have cancer, depression, bowl diseases etc.