What are the effects of low-fat food labels on food consumption? Do people eat more of a snack food when the food is labeled as low-fat? The answer may depend both on whether the snack food is labeled low-fat and whether the label includes serving-size information. An experiment investigated this question u

What
are the effects of low-fat food labels on food consumption?
Do people eat more of a
snack food when the food
is labeled as low-fat? The
answer may depend both
on whether the snack
food is labeled low-fat and
whether the label includes
serving-size information.
An experiment investigated this question using
university staff, graduate students, and undergraduate students
at a large university as subjects. Subjects were asked to evaluate
a pilot episode for an upcoming TV show in a theater on campus and were given a cold 24-ounce bottle of water and a bag
of granola from a respected campus restaurant called The Spice
Box. They were told to enjoy as much or as little of the granola
as they wanted. Depending on the condition randomly assigned
to the subjects, the granola was labeled as either “Regular Rocky
Mountain Granola” or “Low-Fat Rocky Mountain Granola.”
Below this, the label indicated “Contains 1 Serving,” or “Contains 2 Servings,” or it provided no serving-size information.21
Twenty subjects are assigned to each treatment, and their granola bags were weighed at the end of the session to determine
how much granola was eaten.
(a) What are the factors and the treatments? How many
subjects does the experiment require?
(b) Outline a completely randomized design for this experiment. (You need not actually do the randomization.)