Experiments are one of many methods
available to the social scientist. Unlike all other methods, however,
experiments allow the researcher to specify cause and effect. What
are the basics of experiments?
What defines an
experiment?
Experimental
treatment
procedure or substance to
investigate
Use of at least two
groups
control group
does not get
treatment
experimental group
gets
treatment
An experiment may have many
groups
Toothpaste example
Does toothpaste and brushing
lead to fewer cavities?
How can we test?
Set up two groups, and
randomly assign to:
control group
brush with water
three times/day for six months
experimental
group
brush with
toothpaste three times/day for six months
Measure effect of
toothpaste and water brushing with:
number of cavities
after six months
Make both groups have
zero cavities
Time out for some
terminology
Independent Variable
(IV)
toothpaste or no
toothpaste
Dependent Variable
(DV)
number of
cavities
Extraneous
Variables
must be
controlled
Back to the
experiment
After six months count
cavities
If fewer in experimental
group, you can say:
"Toothpaste has been
proven to be an effective dentifrice when used as part of
a regular brushing program."
Recall hypotheses
Here hypothesis
is:
Brushing with
toothpaste will result in fewer cavities
