experimental design Flashcards
(11 cards)
what is matched pairs design
pairs matched on variables that may affect DV
each member is randomly allocated to each condition
2 strengths of matched pairs
-no order effects
-controls participant variables, can be more confident that the results are due to the IV
2 limitations of matched pairs
-large pool of potential participants needed- hard to get+time consuming
-hard to know which variables are appropriate for participants to be matched
what is independent groups design
participants only experience one condition of the IV
2 strengths of independent groups
-no order effects as p’s do 1 condition only
-eliminates demand characteristics- p’s only aware of 1 condition
2 limitations of independent groups
-no control over participant variables- different abilities of participants in the various conditions can cause changes to DV. if more p’s with a particular characteristic are randomly assigned to one the groups, it can affect the DV
-more participants needed to gather sufficient data
what is repeated measures design
all participants experience all conditions of IV
2 strengths of repeated measures
-eliminates participant variables, so differences in performance are due to the manipulated variables
-fewer participants needed so not as time-consuming
limitation of repeated measures
order effects- can lead to demand characteristics
what is counterbalancing (2)
-technique to minimise order effects as it stops it from becoming a confounding variable
-participant sample is divided in half- one half completing the two conditions in one order and the other half completing the conditions in the reverse order
how to carry out a matched pairs design experiment (3)
-researcher needs to ensure the 2 groups are matched for key variables eg. IQ scores
-all participants should be assessed for the key variable
-for each person in 1 condition they should be assigned a ‘matched’ person in the other condition
