AP Psychology Daily Video Notes
1.3 Defining Psychological Science—The Experimental Method
Daily Video 1
*Use the chart in video 1.2 notes to fill in Experimental Method*
The Independent Variable causes a change in the Dependent Variable
Independent variable is what you do.
Dependent variable is what you get.
Hypotheses: If then statement
If ____________________________, then ___________________________________________.
Term
Definition
Experimental
Control
Holding everything else constant
Placebo:
fake treatment—something that is close to
the independent variable, but missing
something
Placebo Effect
The change, due to a belief in the
independent variable
Experimental
Group
group that receives independent variable
Control Group/
Placebo Group
group (without special treatment or with
placebo) to compare to experimental
group(s)
Example Experiment
Random sample/
Random Selection
everyone in the population has an equal
chance of being selected to participate in
the study
Representative
sample:
a smaller group that gives a “snapshot” of
the total population
Random
assignment:
Each participant has an equal chance of
being put into either the experimental
group or the placebo group.
researcher randomly assigns participants to
the experimental or control group
Confounding
variables:
Other items that could effect the outcome
of the experiment (other than the
independent variable alone)
Stratified sample:
the population is divided into relevant
subcategories & a random sample is taken
from each subcategory
Daily Video 2
All experiments have certain things in common
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Hypothesis:
Independent Variable:
Dependent Variable:
Experimental Group:
Control Group:
Placebo Group:
Random Assignment:
Practice 1:
What is the hypothesis? (work the word prediction in there)
What is the independent variable?
What is the dependent variable?
Practice 2:
Identify the experimental group.
Identify the control group.
Describe how Dr. Schmidlap could do random assignment.
Practice 3:
What is the hypothesis? (work the word prediction in there)
What is the independent variable?
What is the dependent variable?
Practice 4:
Identify the experimental group.
Identify the control group.
Describe how Dr. Harlow could do random assignment.
Multiple Choice Practice