Chapter 6

Experimental mortality

A differential loss of subjects from experimental and control groups that affects the equivalency of groups; threat to internal validity.

Control group

A group of subjects that does not receive the experimental treatment or test stimulus.

Experimental group

A group of subjects that receives the experimental treatment or test stimulus.

Research design

A plan specifying how the researcher intends to fulfill the goals of the study; a logical plan for testing hypotheses.

Correlation

A statement that the values or states of one thing systematically vary with the values or states of another; an association between two variables.

Effects-of-causes approach

An approach to causal questions that starts with a potential cause and works forward to measure its impact on the outcome. Emphasis is on measuring the size of the effect that a cause has on an outcome.

Causes-of-effects approach

An approach to causal questions that starts with an outcome and works backward to the causes. Emphasis is on identifying causes of outcomes.

Classical randomized experiment

An experiment with the random assignment of subjects to experimental and control groups with a pretest and posttest for both groups.

Demand characteristics

Aspects of the research situation that cause participants to guess the purpose or rationale of the study and adjust their behavior or opinions accordingly.

Selection bias

Bias due to the assignment of subjects to experimental and control groups according to some criterion and not randomly; threat to internal validity.

Experimental effect

Effect, usually measured numerically, of the experimental variable on the dependent variable.

______ is the extent to which the results of a study can be generalized across populations, times, and settings and is the touchstone for natural and social scientists alike.

External validity

______ means that the research procedure demonstrated a true cause-and-effect relationship that was not created by spurious factors.

Internal validity

Pretest

Measurement of variables prior to the administration of the experimental treatment or manipulation of the independent variable.

Which of the following was identified as a basic component of the most classical randomize experiments?

Pretests are administered.

Large N studies

Quantitative research designs in which the research examines many cases of a phenomenon.

Small N studies

Research designs in which the research examines one or a few cases of a phenomenon in considerable detail.

Experiment

Research using a research design in which the researcher controls exposure to the test factor or independent variable, the assignment of subjects to groups, and the measurement of responses.

______ can creep into a study if subjects are picked (intentionally or not) according to some criterion and not randomly.

Selection bias

External validity

The ability to generalize from one set of research findings to other situations.

Internal validity

The ability to show that manipulation or variation of the independent variable actually causes the dependent variable to change.

Stimulus or test factor

The independent variable introduced and controlled by an investigator in order to assess its effects on a response or dependent variable.

Randomization

The random assignment of subjects to experimental and control groups.

A ______ assertion suggests that a change in one thing brings about a change in another.

causal

When research is conducted in such a way that all possible joint causes of X and Y have been eliminated it is referred to as the elimination of ______.

confounding factors

A statement that two things are systematically related is referred to as a(n) ______.

correlation

Causal relationships express three characteristics including time order, elimination of alternative causes, and ______.

covariation

The group that receives the treatment or test stimulus or factor under study is called the ______.

experimental group

Which of the following terms refers to a differential loss of subjects from experimental and control groups that affects the equivalency of groups?

experimental mortality

All of the following are true of a causal relationship EXCEPT ______.

it demonstrates spuriousness

When membership in a group is a matter of chance and not self-selection it is called ______.

randomization

A ______ is a plan that shows how a researcher intends to study an empirical question.

research design

The classical randomized experiment begins with ______.

sampling

Research designs in which the research examines one or a few cases of a phenomenon considerable detail are referred to as ______.

small N studies

A relationship in which two variables appear to be related only because both are affected by a third variable is called a(n) ______ relationship.

spurious

The most important design of classical randomized experiment is the ______.

stimulus

A ______ is a stimulus given to a treatment group in an experiment.

test factor

The process of measuring the dependent variable prior to the experimental stimulus is referred to as ______.

test-subject interaction

If a study population is not representative of a larger population, which of the following would be limited?

the ability to generalize about the larger population