Experiments
What is manipulated by the experimenter in a lab experiment: the IV or the DV?
The IV
What is random sampling?
When every member of the target population has an equal chance of being selected.
What is repeated groups design?
The same participants are used in both conditions.
What are the two types of hypotheses?
What types of graphs show correlations?
Scatter graphs.
Field experiments have high _________ validity.
Ecological
What is a strength of stratified sampling?
The researcher has identified important subcategories within the sample, it should be representative of the target population and the results can be generalised.
What is a strength of repeated group designs?
Participant variables are kept constant. Therefore, cause and effect can be inferred.
What is a directional hypotheses?
A type of alternative hypotheses that predicts the direction of the effect or difference.
What is a correlation coefficient?
A number which shows the level of correlation, which is between -1 and +1.
In a Quasi Experiment, what already exists that the experimenter has no control over?
The IV
What is a weakness of opportunity sampling?
It is unrepresentative and often biased as students are often used, who are more educated than most people.
What is a strength of independent group design?
Demand characteristics are less of problem.
What is a non-directional hypotheses?
A type of alternative hypotheses that predicts a difference but not in a certain direction.
What is a strength of correlational studies?
It is more ethical than experiments.
Value when doing exploratory research.
Valuable when measuring the strength of relationships.
What are the two weaknesses of a natural experiment?
Difficult to control extraneous variables.
Studies are more difficult to replicate.
What is a strength of volunteer sampling?
Convenient, and little effort is required.
It is more ethical.
What is a weakness of independent group designs?
Participant variables are not kept constant.
What is a null hypotheses?
What is a weakness of correlational studies?
Cannot infer cause and effect.
Spurious relationships.
Cannot measure non-linear relationships.
What are demand characteristics and what type of experiment do they tend to come up in?
Demand characteristics refer to clues or signals in an experimental setting that hint to participants about the experimenter’s expectations, leading them to behave in a certain way to match these expectations, which could bias the results.
Lab Experiment.
What is systematic sampling?
A sample is obtained by selecting every nth person. This numerical interval is applied consistently.
What is matched pairs design?
Different but similar participants are used in each condition. Effort is made to match participants on important characteristics that may effect performance in the particular study.
In what other studies can null and alternative hypotheses can be used?
Correlations
What is the difference between correlations and experiments?
Correlations look at the relationship between 2 co-variables. Experiments investigate the difference between 2 or more conditions.