experimental designs Flashcards
1
Q
Experimental design
A
- how to group/organise ppt in conditions
2
Q
Types of experimental designs
A
- independent groups
- repeated measures
- matched pairs
3
Q
Definition of independent groups design
A
- ppts take part in one condition only
- each condition has different group of ppts
4
Q
How to conduct an independent groups design
A
- group of ppts recruited
- then split into equal sized groups
- different group is allocated to each condition
5
Q
Strength of independent groups - AO3 - no order effects
A
- no order effects
- ppts only take part in one condition
- will not get bored/fatigue
- or better at task/have lasting effects of last condition
- (CONTEXT)
- unlike repeated measures
- where ppts take part in all conditions
6
Q
Strength of independent groups - AO3 - inappropriate
A
- used when repeated measures design inappropriate
- e.g. quasi experiment looking at gender differences
- (CONTEXT)
- each condition needs different ppts
7
Q
Limitation of independent groups - AO3 - individual differences
A
- individual differences affect DV
- as separate groups of ppts in each condition
- e.g. some ppt have better memory (CONTEXT)
- lowers internal validity
- unlike repeated measures
- uses same group in all conditions
- reduce effect of individual differences
8
Q
Limitation of independent groups - AO3 - more ppts
A
- more ppt needed
- as two different groups
- required for different conditions (CONTEXT)
- unlike repeated measures
- uses less ppts as every ppt takes part in all conditions
9
Q
Definition of repeated measures design
A
- all participants
- take part in all/both conditions
- of the experiment
10
Q
How to conduct a repeated measures design
A
- ppts complete one condition
- after sufficient time complete other condition
- task (DV) should be different but match on difficulty / measure same thing
11
Q
Strength of repeated measures - AO3 - individual differences
A
- individual differences between ppt
- in each conditions removed
- e.g. IQ as confounding variables as all ppt same
- (CONTEXT)
so researcher can be sure any changes in DV - due to IV not any other variables
- increase internal validity
- unlike independent measures
- different ppt in different conditions
- so individual differences could affect DV
12
Q
Strength of repeated measures - AO3 - fewer ppts
A
- requires fewer ppt
- same ppts take part in all conditions (CONTEXT)
- unlike independent groups
- searate groups needed for separate conditions
13
Q
Limitation of repeated measures - AO3 - order effects
A
- order effects may occur
- ppts take part more than one condition
- may perform worse 2nd condition - boredom/fatigue
- may perform better 2nd condition - practise
- may be lasting effects from condition 1 to 2 (CONTEXT)
- lowers internal validity
- unlike independent groups
- ppts only take part one condition
- not susceptible to order effects
14
Q
Limitation of repeated measures - AO3 - demand characteristics
A
- increased chance demand characteristics
- ppts take part in all conditions
- may pick up on clues given by researcher
- spend much more time with them
- change their natural behaviour
- help or hinder research (CONTEXT)
- lowers internal validity
- unlike independent groups design
- ppts less likely pick up on clues
- only take part in one condition
15
Q
Definition of matched pairs design
A
- ppts matched on important characteristics
- e.g. age or IQ
- by giving them appropriate test
- match two ppt with same score
- each member of pair randomly allocated
- across each condition
