control of variables Flashcards
Why do you control extraneous variables?
To show experiments result are cause and effect
What is an extraneous variable?
- All variables (which are not the IV)
- Could effect results of investigation
What are four types of extraneous variables?
- Situational variables
- Participant variables
- Investigator effects
- Demand characteristics
What is confounding variables?
- Systematically change with IV
- Cannot show if change in DV is caused by IV or confounding variables
What is demand characteristics?
Any cue from the researcher or research situation that may reveal the aim of the study
What is investigator effects?
Effect of investigator’s behaviour on the outcome of the investigation
What is randomisation?
The use of chance when designing investigations to control for the effects of bias
What is standardisation?
Use exactly the same formalised procedure for all participant in a research study
What is a control group?
- Setting up a comparison
- Help establish causation
What is inter-rater reliability?
Independent raters rate same behaviour as researcher – check for agreement
What is situation variables?
Aspects of the environment that might affect the participant’s behaviour
How to reduce situation variables?
Standardised procedures
What are examples of situation variables?
e.g. noise, temperature, lighting conditions
What is participant variables?
Each participant varies from the other, and how this could affect the results = individual differences
What are examples of participant variables?
e.g. mood, intelligence, anxiety, nerves, concentration
