Question

Do people eat more of a snack food when the food is labeled as low-fat? Do people pay attention to serving size? The answer may depend on whether the snack food is labelled low-fat and whether the label includes serving-size information. A study investigated these two questions using staff, grad students, and undergrad students at a large university as subjects.   
Subjects were asked to evaluate a pilot episode for an upcoming TV show at a theater on campus and were given a bag of granola from a respected campus restaurant. They were told to enjoy as much or as little of the granola as they wanted. Each granola bag had two labels: Twenty subjects were assigned to each treatment, and their granola bags were weighed at the end of the session to determine how much granola was eaten.

Lable1: type	Lable2: serving size
"Regular Rocky Mountain Granola"	"Contains 1 Serving"
"Low-Fat Rocky Mountain Granola"	"Contains 2 Serving"
	no serving-size information

a) Is the study an observational study or an experiment? Specifically in this study (do not give general definitions),

what are the b) experimental units (abbreviated EU, also called individuals or subjects)

c) response variable and whether it is quantitative or categorical

d) How many factors were there and what were they?

e) How many treatments were there and what were they?

f) How many experimental units were in the study?

Answer 1

a) The study us an observational study.

b) The experimental units are the staff, grad and undergrad students who were divided in groups of twenty and were given granola bags to make desired level of inferences about the questions in the study.

c) The response variable is the weight of the granola bags at the end of the session to determine how much granola was eaten. So the response variable is quantitative in nature.

d) There were 2 factors in the first treatment which are labels of the bags as regular and low fat.

And there were 3 factors in the second treatment which were the serving sizes namely 1 serving, 2 serving and no information given.

e) There were two treatments which were type label on the bag and the serving size.

f) Since there were a total of 6 different combination of treatments and 20 units were assined to each combination of treatment we have a total of 120 experimental units in the study.