kjd

Experimental Method

A deliberate change is made to an IV in order to measure its effect on the DV.

Hypothesis

A clear

Directional Hypothesis

States the direction of the difference or relationship.

Non-directional Hypothesis

Does not state the direction of the difference or the hypothesis.

Null Hypothesis

States there will be no difference or relationship.

Independent Variable (IV)

Some aspect of the experimental situation that is manipulated by the researcher — or changes naturally — so the effect on the DV can be measured.

Dependent Variable (DV)

The variable that is measured by the researcher. Any effect on the DV should be caused by a change in the IV. Extraneous Variables (EV)

Randomisation

The use of chance methods to control for the effects of bias when designing materials and deciding the order of experimental conditions.

Standardization

Using exactly the same formalised procedures and instructions for all participants in a research study.

Confounding Variables

A variable that is not included in an experiment

Operationalization

Clearly defining variables in terms of how they can be measured.

Laboratory Experiment

The researcher manipulates the IV in a controlled environment. Field Experiment

Natural Experiment

The researcher has no control over the IV; someone or something else does. Quasi-Experiment

Population

The entire group of individuals who are the focus of the researcher’s interest

Random Sampling

A sample of participants produced by using a random technique such that every member of the population being tested has an equal chance of being selected.

Opportunity Sampling

Participants are asked if they would like to participate as they walk past.

Stratified Sampling

The population is divided into smaller 'strata' based on specific characteristics. After stratification, a random sample is selected from each stratum, ensuring that each subgroup is adequately represented in the overall sample

Systematic Sampling

A sample is produced by selecting every nth person