___1. The variable which the researcher measures and directly manipulates. It is usually
what the researcher thinks will affect the dependent variable.
___2. The variable which the researcher holds constant (controls) during an experiment. It is also
known as a constant variable or simply as a "control".
___3. Also called as spurious variable, is an attribute or characteristic that the researcher cannot
directly measure because their effects cannot be easily separated from those of other
variables, even though they may influence the relation between the independent and the
dependent variable,
___4. A variable that, although not intervening between the independent and dependent
variables, influences the nature and strength of their cause-and-effect relationship.​