| |
| Chapter 3 |
|
| Abscissa
|
the horizontal axis (or X-axis)
in a graph |
| Baseline
|
a measurement used as the basis for
comparison, usually when no treatment is given |
|
Between-subjects design |
an experimental design in which each
subject is tested under only one level of each
independent variable |
| Ceiling
effect |
see Scale attenuation effects
|
| Control
condition |
an experimental condition, usually
with no treatment, used as a baseline |
| Control
group |
a group of participants given no
experimental treatment
|
| Control
variable |
a potential independent variable that
is held constant in an experiment |
|
Counterbalancing |
a term describing any technique used
to vary systematically the order of conditions in an
experiment to distribute the effects of time of testing
(for example, practice and fatigue), so they are not
confounded with conditions
|
| Critical
experiment |
a key experiment that purports to
distinguish among competing theories |
| Data |
the scores obtained on a dependent
variable |
| Demand
characteristics |
those cues available to subjects in
an experiment that may enable them to determine the
purpose of the experiment or what is expected by the
experimenter |
| Dependent
variable |
the variable measured and recorded by
the experimenter
|
| Differential
carryover effects |
a problem in within-subject
experimental designs when exposure to earlier conditions
alters behavior on later conditions |
| Double blind
|
an experimental technique in which
neither the subject nor the experimenter knows which
subjects are in which treatment conditions |
| Experiment
|
the systematic manipulation of some
factors in the environment to observe the effect of this
manipulation on behavior |
| Experimenter
effects |
artifactual results due to the
presence of an experimenter
|
| Floor effect
|
see Scale attenuation effects
|
| General
practice effects |
the tendency for performance to
improve with repetition
|
| Hawthorne
effect |
the condition in which performance in
an experiment is affected by the knowledge of
participants that they are in an experiment; see
Demand characteristics |
| Independent
variable |
the variable manipulated by the
experimenter |
| Interaction
|
an experimental result that occurs
when the levels of one independent variable are
differentially affected by the levels of other
independent variables |
| Level |
the value of an independent variable
|
| Matching
|
attempting to make different groups
of subjects equivalent based upon subject
characteristics or scores on tests |
| Mixed design
|
an experimental design containing
both within and between subject independent variables
|
| Null result
|
an experimental outcome in which the
dependent variable is not influenced by the independent
variable |
| Ordinate
|
the vertical axis (or Y-axis)
in a graph |
|
Quasi-experiment |
an experiment in which the
independent variable occurs naturally and is not under
direct control of the experimenter |
| Random
assignment |
a procedure that ensures each
subjects has an equal chance of being assigned to
experimental treatments |
| Random
selection |
a procedure that ensures each member
of a population has an equal chance of being a
participant in an experiment |
|
Randomization |
a statistical sample procedure where
every element has an equal probability of being selected
|
| Regression
artifacts |
an artifact in the measurement of
change on a variable when groups of subjects who scored
at the extremes on the variable are tested again (see
Regression to the mean) |
| Regression
to the mean |
the tendency for extreme measures on
some variable to be closer to the group mean when
remeasured, owing to unreliability of measurement
|
| Sampling
|
in statistics the selection of
subjects or items for experiments |
| Small n
design |
research design using a small number
of subjects |
| Stability
|
when a dependent measure yields the
same score in repeated experiments given the same
subject, same levels of the independent variable, and so
forth |
| Subject
variable |
a characteristic of people that can
be measured or described but cannot be varied
experimentally (for example, height, weight, sex, and
IQ)
|
| Synergism
|
another term for interaction in which
the joint effects of two variables combine in a way that
is not a simple function of their individual effects
|
| What-if
experiment |
an experiment performed to see what
might happen rather than to test a specific hypothesis
|
