Extraneous and Confounding Variables

Question 1

Extraneous Variables

Answer 1

any variable that influences the DV other than the IV. Variables need to be controlled or removed. They stay the same in all conditions

Question 2

Confounding Variables

Answer 2

Variable that influences the DV other than IV but changes between conditions.

Question 3

Types of EVs

Answer 3

Participant variables - particular to person, situational variables - particular to setting, order effects - order impacts natural behaviour, investigator effects - researcher unintentionally or intentionally influences outcome, demand characteristics - aim of study is predicted or discussed so patients change their behaviour. please-U effect or screw-U effect.

Question 4

Dealing with EVs and CVs

Answer 4

single/double blind procedure, random allocation, randomisation, standardisation

Question 5

Blind Procedure

Answer 5

Single - patient don’t know which condition in - demand characteristics
Double - patient and researcher don’t know which condition in - demand characteristics and investigator effects

Question 6

Random Allocation

Answer 6

Patients randomly allocated - investigator effects and participant variables, bias

Question 7

Randomisation

Answer 7

refers to use of chance methods to reduce researcher’s unconscious bias - investigator effects, order effects.

Question 8

Standardisation

Answer 8

procedures used are kept the same. Keep identical. e.g. standardised instructions - all effects.