Experimental design

what is a independent group design

different ppt are allocated to each conditions of the experiments

what are strengths to an independent group design

• no order effect-improving internal validity

• lower chances of demand characteristic

what are limitations to an independent variable

• participant variables-reduces internal validity

• requires more ppt-less practical, more expensive

what is a repeated measure design

the same ppt take part in all conditions of the experiment

what are strengths to the RMD

• ppt variable are controlled- increases internal validity

• requires fewer ppt

what are limiations to the RMD

• order effect may interfere with the DV-lower validity

• greater risk of demand characteristics

what is the Matched pair design

differents ppt are used in each condition but are matched on participant variable e.g age, gender and IQ

What are strengths to the MPD

• controls some participant variable

• no order effect

what are limitations to the MPD

• time consuming and difficult to find closely match participant

• impossible to match on all variables

• requires more ppt

what is the order effect

practice, fatigue, or even boredom

what technique is used to control the order effect

Counterbalancing

what is Counterbalancing

a techniques in repeated measure design to control for order effects.

what does Counterbalancing ensure

that each condition of the experiment is tested in a different order across ppt, so the order effect is balanced rather than eliminated

How is the Counterbalancing done

(ABBA) Half the ppt do condtionsA then B
this way it is distributed evenly