Directional hypothesis – specifically states the direction of the results as it predicts the nature or direction of the outcome. (one tailed hypothesis)
Non-directional – Direction of results is not predicted, can go either direction (two tailed hypothesis)
Null hypothesis – No relationship between the variables being investigate. A null hypothesis is used because it makes a precise prediction that can be disproved, supporting the alternative hypothesis
Alternative hypothesis – Any hypothesis that is not the null hypothesis
Operationalising variables – once the null and alternative hypothesis has been written the experimenter has to operationalize their variables. This is the process of devising a way of measuring a variable.
Reliability – two or more measurements or observations of the same psychological event will be consistent with each other.
Internal validity – has internal validity if the outcome is the result of the variables that are manipulated in the study.
External validity – the extent to which findings can be generalised to settings other than the research setting
Face validity – simply involves an eyeball test, does it look as if its measuring what it should be?
Concurrent validity – involves comparing the results by a new test to an older test.
Predictive validity – ability of the test to predict performance on future tests
Independent variable – the variable that the researcher manipulates and which is assumed to have a direct effect on the dependant variable (CAUSE)
Dependant variable - the variable that is affected by changes in the independent variable (EFFECT)
Extraneous variables – this is a general term for any variables other than the IV that might affect the DV
Demand characteristics – cues in the environment that help the participant work out what the research hypothesis is.
Internal validity controlled by: Single blind technique – a procedure in an experiment where the participants do not know the hypothesis and do not know which condition they are in
Investigator effects – the influence of the researcher whereby their expectations of what the research outcome should be could lead to a self- fulfilling prophecy.
Internal validity controlled by: Double blind technique – where neither the participants nor the research assistant know the hypothesis or the condition they are in
Target population and sampling
Random: A sample in which every member of the target population has an equal chance of being selected
Methods: Names drawn out of a hat, computer generated, numbered list and a number table.
Population validity: representative sample with high population validity
Opportunity: A sample that consists of those people available to the researcher
Methods: researcher would approach people and ask them to take part. Taking advantage of whoever happens to be available
Population validity: High chance sample will be biased, low population validity
Volunteer: A sample where the participants self-select. Volunteering to take part
Method: The researcher…