Research Variables are the variables affecting one's research study. They are the Independent Variable, Dependent Variable, Constant/Controlled Variable, Extraneous Variables and Intervening Variables.
19. There can be only one
independent variable in an
experiment.
This is the factor manipulated
by the researcher, and it produces
one or more results, known
as dependent variables.
Independent
Variable
20. Independent
Variable
If a scientist conducts an experiment to test
the theory that a vitamin could extend a person’s
life-expectancy, then:
The independent variable is the amount of
vitamin that is given to the subjects within
the experiment. This is controlled by the
experimenting scientist.
21. Dependent
Variable
The factor that is measured or
observed; the change that is
brought about or is effected by
the change in the independent
variable.
the “assumed effect” of another
variable.
22. If a scientist conducts an experiment to
test the theory that a vitamin could extend a
person’s life-expectancy, then:
Dependent
Variable
The dependent variable, or the variable
being affected by the independent
variable, is the life span.
26. In language learning and teaching, they are
usually inside the subject’s heads, including
various language learning processes which the
researcher cannot observe.
27. For example, if the use of a particular teaching technique
is the independent variable and the mastery of the
objectives is the dependent variable, then the language
learning processes used by the subjects are intervening
variables.
28. Moderator
Variables
Affect the relationship between
the independent and dependent
variables by modifying the effect the
effect of the intervening variable(s).
29. Typical moderator variables in TESL and language
acquisition research (when they are not the major
focus of the study) include the sex, age, culture or
language proficiency of the subjects.
30. Extraneous
Variables
are factors in the research
environment which may have
an effect on the dependent
variable(s) but which are not
controlled.
31. Extraneous variables are dangerous.
They may damage a study’s validity,
making it possible to know whether the
effect were caused by the independent
and moderator variables or some
extraneous factor.
Extraneous
Variables
32. If they cannot be controlled,
extraneous variables must at least
be taken into consideration when
interpreting results.