"Want to Lose More Fat? Skip Breakfast Before Workout" is the headline of a newspaper article describing a
study comparing people who did endurance training without eating before training and people who ate
before training. Twenty people were assigned at random to one of two six-week diet and exercise
programs. Both groups followed a similar diet and performed the same daily morning exercise routine. The
people in one group did the exercise routine prior to eating, and those in the other group ate first and then
exercised. The resulting data supported the claim that those who do not eat prior to exercising burn a
higher proportion of fat than those who eat before exercising.

(a) What is the population of interest?

U.S. adults
people who do endurance training
people who are trying to lose weight
people who eat breakfast
people who do not eat breakfast

(b) What claim was tested?
Do those people who do not eat prior to exercising gain more muscle mass than those who
eat before exercising?
What is the optimal breakfast for endurance trainers to consume for peak performance?
Do those people who do not eat prior to exercising burn a higher proportion of fat than those
who eat before exercising?
Do those people who do not eat prior to exercising perform better at endurance training?

(c) What additional information would help you decide if it is reasonable to generalize the conclusions of
this study to the population of interest? (Select all that apply.)

if the subjects were randomly selected from the population of endurance trainers
the length of the endurance training
what the subjects in the control group ate
the opinions of the researchers on endurance trainers

(d) Assuming that the people who participated in the study are representative of the people in the
population of interest, do you think that the risk of an incorrect conclusion would have been lower,
about the same, or higher if 10 people had participated instead of 20?

lower
about the same
higher