Experimental designs Flashcards
Define an Independent measures design
Where different ppts are used in each condition of the IV. Means that each condition includes a different group of ppts
How should an independent groups design be constructed (how are they picked)
Random allocation, ensures that each ppt has an equal chance of being picked for each group
Negative factor of independent measures design
time
More people are needed than with repeated measures = more time consuming
Negative eval independent groups design (differences)
Differences in ppts may affect results, e.g. variations in age
Positive eval independent groups design
Avoids order effects as people only take part in one condition. Stops them from getting tired or fed up
Define a repeated measures design
Where the same ppts take part in each condition. Means that each condition of the experiment includes same group of ppts
Positive eval repeated measures
time
Fewer people are needed as they take part in all conditions. Saves time
Positive eval repeated measures
differences
Ppts variables(individual differences) are reduced as same ppts are used in each condition
Negative eval repeated measures
order
May be order effects. How tired ppts are or how much they know about the experiment can affect their performance and results
Define a matched pairs design
Where pairs of ppts are matched in terms of key variables (e.g. age)
One is put in the experimental group, and the other the control group
Positive eval for matched pairs
ppt
Reduces ppt variables as ppts are in a condition with similar people
Positive eval matched pairs
effects
Avoids order effects
Negative eval matched pairs
Time consuming finding closely matched pairs
Negative eval matched pairs (matching)
Impossible to match people exactly
Negative eval matched pairs (data)
If one ppt drops out, you lose 2 ppts data
