Mr. Gilbert
Psychology
Experimental Design Performance Assessment
NAME:________________
DATE:________________
DUE: Friday, January 21
PSYCHOLOGY
EXPERIMENTAL DESIGN
Purpose: You want to market a new soft drink as a mood enhancer. Your mission is to find out if your
soft drink puts people in a better mood by designing an experiment. The experimental or scientific
method uses direct observation in a scientific setting. The empirical method uses direct observation
without the use of science. Experimental methods have shown how cigarettes are dangerous and that
rewards and punishment can modify existing behaviors.
1. You need to create a HYPOTHESIS. A hypothesis is an educated guess. It needs to be stated
in an “if…, then…” fashion. The “if” portion of the hypothesis is the situational statement and
the “then” portion is the consequential statement.
Example: “If you brush your teeth with Crest, you will have fewer cavities than with any other
toothpaste.”
Experiments must be REPLICATED over and over in order to prove its reliability and validity
and to show that there is a good possibility that the hypothesis may be true. If you can support
your hypothesis, through an experiment, you have created a theory. A theory is not always
true: it is a scientifically supported statement that can be true. A hypothesis may be considered
invalid when results don’t support it. In this case, you may be supporting the NULL
HYPOTHESIS.
Example: “If you brush your teeth with Crest, you will not have fewer cavities.” While you
can’t definitely prove a hypothesis, you can disprove one.
2. After you have a hypothesis, explain how you would test it. What is your POPULATION?
(You can use just one age group.) How will you get your SAMPLE and what kind will it be?
How big will your sample be? You need a CONTROL group. The control group will be
tested in the same way as the experimental group except that the independent variable will be
missing. The purpose of the control group is to provide a comparison to the experimental
group. Identify your EXPERIMENTAL group. You are actually testing your hypothesis on
the experimental group. This group receives the independent variable: that which is being
tested to see how it affects behavior. If there is a difference in the responses of the
experimental group compared to the control group, you can accurately see how the independent
variable affects behavior. You should only have one independent variable. If you have more
than one and behavior is affected by them, how do you know which one is effecting behavior in
that way? You need a PLACEBO and a PLACEBO GROUP. What are your
INDEPENDENT and DEPENDENT variables? If you are using feelings about a product as
you D.V., how will you rate those feelings (questionnaire, smiles, etc.)? Make sure you only
have one I.V. List around five variables that should be held constant and list those as
CONTROLLED or CONSTANT variables. List around five variables that you can’t control
and list those as CONFOUNDING variables. It’s best if your sample doesn’t know your
hypothesis. You need to conduct your experiment as a DOUBLE BLIND study.
Mr. Gilbert
Psychology
Experimental Design Performance Assessment
NAME:________________
DATE:________________
DUE: Friday, January 21
3. ANALYZE your data. Make up results and provide me those results. A table, graph, or chart
will come in handy here. The MEAN, MEDIAN, and/or MODE of your findings will prove
useful. (Mean= average distribution of scores [add the scores and divide by the number of
scores] / Median= middle score in a distribution [half the scores are above it and half the scores
are below it] / Mode= most frequently occurring score in a distribution of scores.)
4. Report your findings. This is your CONCLUSION. Did you prove your hypothesis? Do you
now have more questions? What are those questions? Did you see any confounding variables
or realize that there are even more confounding variables? Would you change anything?
5. Note all capitalized words. Have you used them? If not, is it clear why you didn’t? Have you
followed the scientific method (steps 1-4 above)? Have you provided OPERATIONAL
DEFINITIONS for your variables? Be specific. Remember, in order for your experiment to
be reliable and valid, it has to be REPLICATED by others. You will need to type this
experimental design. It can be numbered as I have or you can use the following headings:
HYPOTHESIS, EXPERIMENTAL DESIGN, ANALYSIS, and CONCLUSION.
This experimental design needs to also include a cover page and the scoring guide.
6. Good luck and let me know if you have questions.
Scoring Guide
EXPERIMENTAL DESIGN
PERFORMANCE ASSESSMENT
____/5 cover page
____/5 constant variables
____/1 hypo
____/5 confounding variables
____/1 null hypo
____/5 Data Analysis Page
____/2 sample and pop.
____/5 conclusion
____/2 I.V. and D.V.
____/3 feasibility of design
(does it work, make sense, etc.)
____/3 exp., control, and placebo Group
____/3 vocab. (operational definitions, double blind, replication)
____/4 correct headings (hypo, exp. Design, analysis, conclusion)
____/3 structure (paragraphs, easy to follow, visuals)
TOTAL POINTS: _______ / 47 POINTS
Mr. Gilbert
Psychology
Experimental Design Performance Assessment
NAME:________________
DATE:________________
DUE: Friday, January 21