Unit 6 Flashcards
correlation coefficient
a statistical index of the relationship between two things (from - 1.00 to +1.00).
Illusory correlation
perceiving a relationship where none exists or perceiving a stronger than actual relationship
Regression toward the mean
the tendency for extreme or unusual scores or events to fall back (regress) toward the average
Experiment
a research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant factors.
experimental group
in an experiment, the group exposed to the treatment, that is, to one version of the independent variable.
control group
in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.
random assignment
assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between the different groups.
double-blind procedure
an experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.
placebo effect
experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent.
Confounding variable
a factor other than the factor being studied that might influence a study’s results
Dependent variable
in an experiment, the outcome that is measured; the variable that may change when the independent variable is manipulated,
Validity
the extent to which a test or experiment measures or predicts what it is supposed to
