L8: Control of Extraneous Variables Flashcards
1
Q
What ensures a study has validity?
A
- Controlling EVs to stop them becoming CVs
2
Q
What are Participant Variables?
A
- Characteristic of ppts that could affect the DV e.g intelligence, personality
- Avoided by Matched Pairs & Repeated Measures
- Random allocation like Independent Groups = unibiased groups
- Random allocation is not applicable for a Quasi Experiment
3
Q
How to Randomly Allocate
A
- Place all ppts names in a hat/computer
- Randomly pull names out and assign to a group
4
Q
What are Environmental Variables?
A
- Factors in env that could affect the DV
- Ex. Temperature, lighting, noise
- Standardisation stops this (all conditions, materials, and instructions are the same for all ppts)
5
Q
What are Investigator Effects?
A
- Person collecting data has knowledge about the research aim, and this knowledge affects the data collected.
- Observer bias is a type of Investigator Effects
6
Q
How to prevent Investigator Effects?
A
- Double Blind Technique: neither ppts nor investigators know the hypothesis or their condition
7
Q
How do Investigators influence the results? How do we overcome this?
A
- Physical characteristics of the investigator can influence the behaviour of the ppt (age, gender, ethnicity)
- Standardised scripts should be written to ensure that the investigator acts the same way to everyone.
- Investigator should ask q in a neutral tone
8
Q
What are Demand Characteristics?
A
- Ppts guessing a study’s purpose and doing what is expected
- Ppts either please the researcher by acting correct, or they try to ruin the experiment (Screw-you-effect). They can act unnaturally because of nerves or social desirability bias
- Observer and Interviewer Effects are types of Demand Characteristics
9
Q
How to overcome Demand Characteristics
A
- Single blind technique: participants do not know what condition they are in or what the hypothesis is
- harder in Repeated Measures
