Control of Variables

Question 1

What is an Extraneous variable?

Answer 1

Any variable other than the independent variable (IV), that may have an effect on the dependent variable (DV) if it is not controlled. EV’s are considered to be nuisance variables. (Gender, Age, Time of day, temperature)

Question 2

What is a Confounding variable?

Answer 2

Any variable, other than the IV that may have affected the DV so we cannot be sure of the true source of the changes to the DV. Confounding variables may vary systematically with the IV. (previous knowledge, age)

Question 3

What is Demand characteristics?

Answer 3

Any cue from the researcher from the research situation that may be interpreted by the participants as revealing the purpose of the investigation.

Question 4

What are Investigator effects?

Answer 4

Any effect of the investigator’s behaviour (conscious or unconscious) on the research outcome (the DV).

Question 5

What is Standardisation?

Answer 5

It is using exactly the same formalised procedures and instructions for all participants in a research study.

Question 6

What is Randomisation?

Answer 6

It is the use of chance in order to control for the effects of
bias when designing materials and deciding the order of conditions.

Question 7

Explain one difference between extraneous and
confounding variables

Answer 7

Extraneous variables is any variable, other than the independent variable, which MAY affect the dependent variable if it not controlled, such as age of the participant. On the other hand, confounding variables are any variables, other than the independent, variable that WILL affect the dependent variable, however, these vary systematically with the independent variable, such as personality.