a statement of the procdedures (operations) used to definre research variables. For example, human intelligence may be operationally defined as what an intelligence test measures.
repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances.
an observation technique in which one person is studied in depth in the hope of revealing universal principles.
a technique for ascertaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group.
all the cases in a group being studied, from which samples may be drawn. (note: except for national studies, this doesn't refer to a country's whole population)
a sample that fairly represents a population because each member has an equal chance of inclusion.
observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.
a measure of the extent to which two factors vary together,a nd thus of how well either factor predicts the other.
a statistical index of the relationship between two things (from -1 to 1)
a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation).
the perception of a relationship where none exists.
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.
assigning participants to experimental and control groups by chance, thus minimizing pre-existing differences between those assigned to the different groups.
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
experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipent assumes is an active agent.
in an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.
in an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.