Experiments: Internal validity Flashcards
What is an extraneous variable?
In an experiement, any variable other than the IV that might potentially affect eh DV and thereby confuse the results.
This inclused both ppt and situational variables
How do you deal with extraneous varibles?
Such variables should be held constant, for example all ppt should be a similar age.
Or the researcher must ensure that such variables are randomly spread across conditions.
What is a confounding variable?
This is a special class of extraneous variable- where the extraneous variable changes systematically with the IV.
This means that you cannot be sure than any change in the DV was due to the IV.
In fact the condounding variable is acting as another IV.
How do you deal with a confoudning variable?
They should be identified and controlled before a study is conducted
What is predictive validity?
Concerns the extent to which a test score actuallt is ralted to the behaviour you want to measure
Therefore, the test score can forecast performance on another measure of the same behaviour.
What are demand characteristics?
Cues in research situation that communicate to ppts what is expected of them and may then unconsciously affect a ppts behaviour
How do you deal with demand characteristics?
In the example on the left it might be better to use an independent groups design.
