extraneous variables

Question 1

What are 3 types of extraneous variables?

Answer 1

1. Participant variables
2. investigator effects
3. situational variables

Question 2

what is participant variables

example

Answer 2

personal characteristics of participants which can affect dv.

such as iq, gender and mood

Question 3

what are investigator effects?

what is example?

Answer 3

the researcher influences the participants behaviour therefore the results of study.

expectation of researcher.

Question 4

what is situational variables?

Answer 4

extraneous variables that are features of external environment

Question 5

what is demand characteristics

Answer 5

• where participants form an interpreptation of the experiments purpose and unconsciously change thier behaviour

Question 6

what happens when you don’t control extraneous variables?

Answer 6

reduces validity and reliability

Question 7

what are 3 ways we can control extraneous variables

Answer 7

1. standardisation = making everything the same
   - works for situational and investigator effects but not participant variables.
2. match= matching them up for similar characteristics then equally distributing them across groups
   - works for participant variables.
   however this is time consuming + its impossible to control every participant variable.
3. random allocation = randomly assigning each participants to different groups

Question 8

what is single blinding?
what does it help with?

Answer 8

when participants dont know what group they are in
- helps with demand characterisitcs

Question 9

what is double blinding?

Answer 9

when neither participant or researcher knows what group they are in
- helps with investigator effects and demand characteristics.