Term

Definition/Description

Critical
Thinking 
Thinking that does not
blindly accept arguments and
conclusions

Control
Variable 
Factor that is held
constant in an experiment, so
that it is not allowed to
vary.

Independent
variable 
Factor for which the
researcher manipulates
at least two levels in order
to determine its effect on
behavior (on experience).

Individual Difference Variable 
 Research Participates are
selected into different
groups based on a
characteristic or trait
that varies consistently
across individuals
 Also called a predictor
variable, a subject
variable, or a
quasiindependent
variable
 Causation cannot
easily be determined.

Dependent
Variable 
 A measure of behavior (or
experience) that is used
to assess the effect (if
any) of the independent
variable or the
relationship between
itself (the dependent
variable) and an individual
difference variable.
 Dependent variables that
relate to individual
difference variables are
sometimes called
‘criterion
variables’
 Must beadle to change the
dependant variable into a
number

Operational
Definition 
the procedure
whereby a construct is
defined solely in terms of
the operations used to
produce and measure it

Random Sample 
A
sample that fairly represents
a population because each
member has an equal chance of
inclusion in the sample

Random
Selection 
Every
participant has an equal
chance of being in the study
as a whole.

Random
Assignment 
Every
participant has an equal
chance to be in the
experimental (vs the control)
aspect of the procedure.

Properties a
Case Study 
Single participant
Historical/ qualitative
(often not reduced to
numbers) analysis
Useful for generating
hypotheses to be tested with
further studies and
experiments

Properties of
a Correlation Study

Many participants
Operational definition
Descriptions statistics,
quantitative data (means,
medians, correlation
coefficients)
Inferential statistics, the
probability that the result
of at least this size is due
to change is calculated
Can determine a significant
relationship, but NOT
whether one variable CAUSES
changes in another variable.

Properties of
an Experiment 
Many participants
Operational definitions
The independent variable is
manipulated and alternative
hypothesis are eliminated
(often by using Random
assignment to conditions)
Descriptive statistics
Inferential statistics
Can Determine if one variable
causes changes in another
variable.

Mean 
(average)
volume of participants voice
measured in decibels by a
sound meter over a 20 minute
period while responding to a
set of provocative questions
EEG (electroencephalogram)

Example

Measure of central
tendency
10,000,000
50,000
40,000
30,000
12,000
12,000
10,000


Mean: 10,154,000/7
= 1,450,571.43 (average)
Median: 30,000
(midpoint of the distribution of
scores after ordered from
"high" to
"low")
Mode: 12,000
(most frequently occurring score) 