Experimental Design Flashcards
What is an independent groups experimental design?
Different participants are allocated to two (or more) experimental groups representing different levels of the independent variable. There may be a control group who do not take part in any IV manipulated condition
What are the strengths of an independent groups experimental design?
1) No order effects as participants are only tested once so they can’t improve on the task as they don’t repeat it
2) Less chance of guessing the aim as they only do the test once and reacting to demand characteristics is less likely as behaviour doesn’t change.
What are the weaknesses of an independent groups experimental design?
1) There is no control of participant variables so could get a more intelligent or younger group compared to other group which affects the IV that is being tested.
2) Needs more participants than with a repeated measures design meaning the sample side is smaller.
What is a repeated measures experimental design?
Each participant takes part in every condition being tested and each condition represents one level of the independent variable.
What are the strengths of a repeated measures experimental design?
1) Good control of particiant variables because the same person is tested
twice. We can be sure the IV is what is affecting the DV.
2) Fewer participants are needed than with independent groups design so a
larger sample make the results more dependable.
What are the weaknesses of a repeated measured experimental design?
1) Order effects are produced- a participant may be better on the second
test because of getting better with experience.
2) Participants may guess the purpose of the experiment because they do both conditions and change behaviour to prove it.
What is a matched pairs experimental design?
Different but similar participants in each condition of the study. Participants are matched upon a certain trait such as gender, IQ, age etc.
What are the strengths of a matched pairs experimental design?
1) Controls for participant variables because of the matching pairs - know that the IV is what’s affecting DV.
2) Avoids order effects because participants are only tested once so can’t improve on the task as they don’t repeat it.
What are the weaknesses of a matched pairs experimental design?
1) Very time consuming to match participants on key variables - may not have time or funds to do this.
2) May not control all participant variables because you can only match on variables known to be relevant, but it could be that other variables are important but this is not realised.
