Preserving the Validity of a Study

Question 1

What are extraneous variables?

Answer 1

Factors, other then the IV, that may influence the DV.

Question 2

Name the three types of extraneous variables.

Answer 2

1) Participant variables
2) Situational variables
3) Experimenter variables

Question 3

What are participant variables?

Answer 3

Qualities of the pps that may influence the DV E.g. intelligence or age.

Question 4

What are situational variables?

Answer 4

Qualities of the experiment’s setting that influence the DV. E.g. temperature and noise levels.

Question 5

What are experimenter variables?

Answer 5

Qualities of the researcher that influence the DV - e.g. gender, tone, appearance - female researchers may provide different results to male ones.

Question 6

What are investigator effects?

Answer 6

Physical characteristics of the researcher that influence the outcome of the result. E.g. age, gender and ethnicity.

Question 7

How would investigator effects be reduced?

Answer 7

Using a double-blind study reduces investigator effects - as neither the researcher or the pps know which condition they are in.

Question 8

Define what is meant by ‘concurrent validity’.

Answer 8

Close agreement between the data produced by the new test compared to the established test. Close agreement is indivcated if the correlation between the date produced is greater than +0.8.

Question 9

How is face validity meaured?

Answer 9

Asking others whether the methodology chosen is a good measure of the dependent variable. E.g. whether the number of verbal errors is a good measure of verbal fluency.