Experimental design Flashcards
what is an independent group?
Each participant only undertakes one condition – some experience the IV, some act as the control.
what is repeated measures group?
Participants experience each condition.
what is a matched pairs group?
Two different groups of participants are used. Characteristics thought to be relevant to the study are identified and participants are paired on these variables. One member of each pair has to be placed in each condition.
what are the strengths of using an independent group?
As each participant undertakes one condition there is no risk of order effects and reduced risk of demand characteristics.
what are the strengths of using a repeated measures group?
As participants act as their own control, individual differences are controlled. More economic than independent measures.
what are the strengths of using a matched pairs group?
As each participant undertakes one condition there is no risk of order effects and reduced risk of demand characteristics. Individual differences have been managed by the matching process.
what are the weaknesses of using an independent group?
Individual differences there maybe a bias in the characteristics or abilities of participants that affects performance on conditions. More participants are needed than repeated measures.
what are the weaknesses of using repeated measures group?
order effects, the second condition maybe benefitted by practice or undermined by fatigue or boredom. The second condition in contrast to the first might reveal the hypothesis and the participant could change their behaviour on the second condition. (Demand characteristics).
what are the weaknesses of using matched pairs group?
It is very time consuming and costly to match participants on key variables. As a result samples maybe small with implications for reliability. It may not control on all variables because you are only matching on variables known to be relevant.
how can the weaknesses of using an independent group be over come?
Participants should be randomly allocated to conditions e.g. participant names should be ‘pulled out of the hat’ alternating conditions.
how can the weaknesses of using matched pairs group be over come?
counterbalancing should be used to avoid order effects. Each condition is tested first or second in equal amounts.
how can the weaknesses of using matched pairs group be over come?
A pilot study may need to be conducted to identify key variables.
Name two British Psychological Society (BPS) Code of Ethics.
Respect individual and cultural differences, Confidentiality,Competence, Informed consent,Discomfort and distress,Right to withdraw, Debriefing and Privacy
