Control of EV

Question 1

types of ev

Answer 1

• order effects : ppt is tired to practiced for second condition
• investigator effect : behaviour of the investigator changes ppt behaviour/affects DV measured
• situational variables - factors in environment like sound
• participant variables - differences within individuals in different groups

Question 2

ways to reduce

Answer 2

• order effects = counterbalance
• investigator effects = double blind
• situational variables = standardised procedure
• ppt variabes = matched pairs and random allocation