Chapter 2-Doing Psychological
Eg. Domestication of pets is a good thing
Types of Descriptive
Derive testable hypothesis.
Studies (Classification of variables) -Make sure that it specifies relationships
• Case Study (ex: Freud) a between events or variables.
detailed description of one person (characteristic/trait/behavior that can be
over time and in depth. Used in measured)
clinical settings. Eg. Pet owners are healthier than non-pet
• Observational Study involves Variable #1- pet owners.
more people. When you watch and Variable #2- health.
record behavior without interfering
Want to be even more specific.
Operational definitions a way of
• Tests/ Assessment defining variables that specifies the
instruments often a logistic way
of collecting dat. operations or action we use to measure
those variables. Precision is key.
Uniform test taking and 1 Dog, sterile , 3 year old
HealtIs your test measuringood
scoring procedures to pressure –what you think it’s
gather norms. The scores are measuring?happiness –
consistent life satisfaction
SStandardization ReReliability VValidity
Norms retest e Content CrCriterio
Norms retest e Content n n
Scores Give two Your
remain the versions content Does your
same of the adequately test predict
across two same reflects that are
testing’s. test. your related to
Survey (a lot of tests put together in a mass format/ a
combination of tests)
Volunteer ’s differ from non-volunteer.
• Self-report data is subject to social desirability bias. (We
want to appear in a positive light.)
• Response bias phrasing your questions affects the
• What is a correlation? A measure of how strongly two variables are
related and the direction of that relations.ip
o Direction positive or neg. correlati.n
Positive correlation: when something is increasing
together OR decreasing together. Are they moving in the
same direction? (The more you’re exposed to something,
the more you like it.)
Negative correlation: (inverse relationship) the 3
variables change in different directions. The scores go in
opposite directions. (The more you smoke, the less healthy
o Strength: coefficient of correlation (r)
o The range that the strength correlation ranges from +1 to -1. -1
being perfect negative (for every one unit change in one variable
the other variable changes one unit as well). +1 being perfect
positive. A strong relationship is 7-10. A weak relationship is from
Advantages/Disadvantages of Correlational studies
• Breadth of knowledge
- a lot of information
- Complex relationships .
• Illusory Correlations (sound like they go together, but don’t. Not
empirically supported.) e.g. superstition.
• Lack of Causation a potential 3 variable associated with the other
+r(# appliances, birth control use)
--------- Education ----------
Experimental Studies – When we test causation.
1. Manipulate something.
2. Control all else.
a. Control group
b. Random Assignment
No scientific study is perfect, better studies can always be done. 5
Indeepenndenntvaarabble Deepeendeent variable
(whatthe expermeenter (what s meassuedd
vares/maanpuuates asa funcion
caausesto happen) ofhe IV)(outcome)
Exxpeermeenntal A good control
Coonntollconnditon condition is
(he presence (absence ofthe V)) condition in every
of he IV) possible way
Give people a pet. No pet. except the IV
Assign participants to either Experimental groups or Control groups
via Random assignment: participants have equal chance of being
assigned to either experimental or cont.ol condition 6
Why? Does R.A. help increase control?
Non Random assignment:
Does studying lead to good grades?
(Independent variable) (Dependent variable)
Participant1 High IQ Participant5 Low
Participant2 High IQ Participant6 Low
Participant3 High IQ Participant7 Low
Participant4 High IQ Participant8 Low
Results: A F
You have not controlled for alternative e