Key Terms
Constants: The factors within an experiment that
are kept the same for all groups or trials in an
attempt to reduce the influence of extraneous
variables.
Control group: The group in an experiment that
receives the exact treatment as the experimental
groups except it does not receive any change of
the independent variable. It is the group to which
the experimental groups are compared.
Dependent variable (DV): The variable in an
experiment that changes in response to the
independent variable and, therefore, is also
referred to as the responding variable.
Experimental groups: The groups or trials in an
experiment that receive all the same conditions
except varying amounts or qualities of the
independent variable.
Extraneous variable: An “undesirable” variable
in addition to the independent variable that
may influence the results of an experiment,
introducing error if it is not, as much as possible,
controlled or significantly decreased in the
research design.
Focal sampling: A behavioral recording technique
where a narrative (i.e., what is called an essay in
English class) is written on every behavior of one
individual or group for a set length of time.
Hypothesis: A tentative (i.e., not final and
definite) and testable proposed explanation for
an observable phenomenon.
Independent variable (IV): The variable in
an experiment that is purposely changed or
manipulated, either in quantity or quality, by the
researcher; also referred to as the manipulated