Experimental design

Experimental design

1. Repeated measures

   • Same ppts do each condition
     • Tested against themselves
       • Different forms of IV
   • Evaluation
     • No participant variables
       • Fewer participants needed
     • Order effects?
       • Could remember something from previous day - practise effect
       • Tired from previous day - fatigue effects

2. Matched pairs

   • Two groups, previously tested w/ same amount of important variables
     • One of each pair is put in either experimental group or control group
   • No order effects
     • Less individual differences
   • Time consuming to match
     • Wont eliminate all individual differences
       • Twice as many ppts as RM

3. Independant groups

   • People randomly allocated to two groups
     • Perform only one of two conditions
   • Evaluation
     • Participant variables
       • More participants required than RM
     • No order effects
       • Less demand characteristics
         • Only perform one condition - dont guess experiment