experimental design

• Experimental design involves ways in which participants are used in an experiment.
• Independent groups are two separate groups of participants who experience two different conditions, one being in the control and the other experimental.
• In independent groups, both groups are controlled and there are no order effects.
• Participants in independent groups only experience one condition and it is less practical.
• Matched pairs is a method where participants are paired on a variable or variables related to the experiment, such as IQ.
• In matched pairs, two people similar with one variable are put into different categories.
• Attempts to control confounding variables are made in matched pairs.
• Matched pairs are less order effective and cost more money for the initial test.
• Repeated measures is a method where all participants experience both conditions.
• In repeated measures, each participant experiences the experimental and controlled conditions.
• Repeated measures are less participant variable and have higher economic value.
• Order effects in repeated measures are controlled by counterbalancing.
• Demand characteristics are a potential problem in repeated measures.
• what are order effects

  • Practical effect – knowing of the first condition improves performance ​
  • Fatigue effect – participants become tired ​
  • Boredom effect ​
  • Counterbalancing – people doing ab the ba (ABBA)