2. There is an old wives tale that drinking
coffee will stunt your growth.
To test this, an experiment will be
conducted to test how coffee effects
growth in humans
4. Population: Children and Young Adults
ages 10-21
Sample: 600 Volunteers who either do
not drink coffee on a daily basis or have
never had coffee before (300 male, 300
female)
5. Volunteers will be blocked by gender, as
females and males grow at different
rates at different times to different
heights (ex: males hit puberty later than
females and are usually taller)
Then, they will be blocked by age into 3
groups: ages 10-13, ages 14-17, and
ages 18-21 since younger people usually
grow more than older people, without
adding in the factor of coffee.
6. After both stages of blocking, volunteers
will be randomly assigned to one of two
treatments:
› Treatment 1: 1 cup of black coffee given per
day
› Treatment 2/Control: 1 cup of a “placebo”
coffee given per day that tastes, smells, and
looks like coffee, but isn’t (made by a
professional barista)
8. Before the experiment is conducted,
subjects’ heights will be recorded
Heights will be measured once per
week, at the same date and time
At the end of 1 year, the subjects’
heights and how they’ve changed will
be compared to those in the same age
and gender group to look for any cause-effect
relationship
9. Double-Blind Experiment
› Subjects participating in the survey will not
be told which treatment they are receiving
(coffee or placebo)
› Evaluators measuring and recording heights
will not know which subjects are receiving
what treatment
› Designers of the experiment will be aware of
which subjects are receiving what treatment
