2. 1. We need a full brain to function completely
2. Drinking coffee can help sober you up
3. Reading in dim light can ruin eyesight
4. Overweight kids are still carrying “babyfat” that will melt
away as they grow
5. Kids raised by homosexual parents have higher rates of
6. Women are worse drivers than men
7. Brainstorming ideas as groups is more productive
8. Most people who are abused as kids become abusers
9. The age group at highest risk of suicide is adolescents
10. Homicide is more common than suicide
11. Nicotine is less addictive than harder drugs
3. ALL of the questions from the previous slide
This is why we need the Scientific Method – we need
to verify answers that we think we know.
We might have heard the answers from a parent,
teacher, friend, internet…… they might have been
right, they might have been joking, they might have
been wrong, they might have been lying!
4. Where do your beliefs, knowledge come from?
Rumor, class, parents, friends, religion, can’t
remember, your experiences?
These are NOT always accurate sources.
Scientific Method = STANDARDIZATION!
minimizes error, rumor, & made up stuff
Replication is easier because we are all using the
same steps in the scientific method.
5. Identify Problem
Theory of “WHY/SOLUTION” for a general issue
1. Formulate a testable hypothesis
2. Design study
3. Collect data
4. Analyze data and draw conclusions
5. Report findings
6. Operationally Define Variables
Choose between research options
Descriptive, Correlation, Experiment
Choose data collection options
Life Outcome Data
7. Operational Definition
Researcher’s description of how the variable will be
used in his/her study.
Reason we need one: people interpret things different;
this is a problem for researchers. If I ask 100 people
how much they ate yesterday, one might say 3
(meaning 3 meals) and someone else might say 2,000
(meaning calories). We don’t want participants to
have to interpret the variable, so we do it for them.
What we need to define:
a) Unit of measurement (need to narrow down to 1)
b) What counts (what situations apply/don’t apply here)
8. Unit of measurement
COULD BE: inches, feet, meters, hands (this is how you
measure a horse). In an operational definition you (as
the researcher) get to choose (1) of these. For instance:
Could be: how many TVs you have, how many hours
you watch, rate quality of yours 1-10 where 1= terrible
and 10=state of the art. You would need to choose
what unit you will be measuring.
9. What Counts
As a researcher you also need to identify what counts
and what doesn’t count and under what conditions
Height: do I measure with my shoes ON or OFF? Do I
measure to the top of the skull or hair (I might have
spikey hair that gives me 2+ inches)? Do I measure all
slumped over or standing with back against a wall? Do I
measure as of today or 5 years ago before I was done
TV: do I measure yesterday’s TV viewing or last week’s?
Do I count when the TV was on in the background, but I
was working on my computer? Do I count when the TV
was on but I was napping? Do I count when I was
watching a TV show streaming to my phone or only the
box on the wall?
Describes existing variable
Looks at Relationships/Associations between two
items (used for future prediction)
Looks at causality between items (used for
11. Psychologists describe existing behavior or
characteristics of individuals engaging in it
Avg age, education level, number of occurrences,
typical environment, etc
13. Examines the relationship between TWO variables
Variables must be
Used for making future predictions
Measure TWO variables from EACH participant
14. Prediction of outcome
Strength and direction
Mild, moderate, strong
Positive or Negative (or description)
15. 1. What is your shoe size?
2. What is your current GPA?
1. What is your golf ability (scale of 1-10)?
2. What is your golf handicap score?
1. What is your annual income?
2. What is your weight in lbs?
16. Correlation Coefficient
a statistical measure relationship between variables
r = +.37
(positive or negative)
(0.00 to 1.00)
17. Positive Negative
X Y X Y X Y X Y
• Golf ability & Golf
• Minutes workout &
• Class attendance &
• Age & Height
• Hours practices &
• Liquid consumption &
frequency of urination
18. How well one
the other. (0-1)
Closer to 1 = better
Closer to 0 – less
19. Three Possible Cause-Effect Relationships
20. We cannot make causal statements as there are
TOO many possible cause and effect options
If I want to know cause and effect, I have to
perform an Experiment.
It is set up different – so we are testing (1) possible
cause and effect relationship.
Method in which one variable is MANIPULATED
under CONTROLLED conditions (IV) and observes
changes in a second variable (DV)
Independent variable (IV) – a condition or event
that is “manipulated” in order to see if it impacts
Dependant Variable (DV) – variable that is thought
to be affected by the IV (measured by the
26. Prediction of outcome
Cause and effect
Which level of IV would do better/worse than
Students taking the test in the No light
condition would receive lower test scores than
those in the low and bright light conditions,
and there would be no difference between
students in the low and bright light conditions.
29. Hypothesis: People who smell
“bad” things will not eat as much as
those who do not smell anything
½ of you will smell a skunk
½ will not smell anything specific
I am going to keep track of (through observation)
who eats more potato chips in 15 minutes
What is the IV (and levels), what is the DV?
Smell in room
Nothing in particular
how much eaten
Operational definition: how many individual chips you
eat in the next 15 minutes
31. Experimental Condition(s)
the condition(s) of the IV that exposes participants to
the “active treatment” or the “non-status quo”
Minimum of 1 experimental condition
the condition of an experiment that is the “non-active
treatment” or the “status quo”
serves as a comparison for evaluating the effect of the
Max of 1 control condition
34. Random Assignment
assigning participants levels/conditions of the IV
Assign to levels by chance
each participant has the exact same likelihood of being
placed in ANY of the conditions
minimizes pre-existing differences between those
assigned to the different groups
Works based in Statistical probabilities
35. Placebo Effect
Occurs when changes in behavior are produced by a
cognitive “decision” rather than the IV itself.
A “fake” substance or condition administered instead of
an “active” agent, to see if it triggers the effects believed
to characterize the active agent
both the research participants and the research staff are
“blind” to whether the research participants have
received the treatment or a placebo
commonly used in drug-evaluation studies
38. Surveys - Participants are asked direct questions about a given
Example: how intelligent are you on a 1-10 scale where 1=not
at all and 10=most ever
Observation – participants are watched to identify their level
on a topic
Naturalistic – in a natural setting
Laboratory – in a laboratory setting
Test Data – Participants are asked indirect questions about a
Example: given an IQ test to interpret how intelligent you are
Life Outcome Data – using existing data sources to pull
what we need
Example: use your existing ACT score to use as Intelligence
measurement rather than taking a new one
all the cases in a group, from which samples may
be drawn for a study
a sample that fairly represents a population
because each member has an equal chance of
A sample of the population. Volunteers who
were available to the researcher.
40. Descriptive statistics- summarized data for large
groups of participants.
Measures of Central Tendency-
A number describing a “typical score,” around which
Add all scores divide by N
Median- midpoint in rank-ordered data
½ scores above, ½ below
Mode- score appearing most often