Unit 8

• Between Subject Design


  Different participants are assigned to each level or condition of the independent variable
• Contrast Effect


  Occurs when participants responses in a later condition are affected by a particular experience they had in an earlier condition
• Counterbalancing


  A method of controlling for order effects in a within-subject design, by either including all possible orders of presentation for conditions or randomly determining the order for each participant
• Fatigue Effect


  When participants preform worse over the course of a study simply because of diminished effort or fewer resources due to the passage of time
• Latin Square Design


  A technique to control for order effects without having all possible orders
• Matched Pairs Design


  A method of assigning participants to conditions in which pairs of participants are first matched on some characteristic and then each member of the pair is randomly assigned to a condition
• Order Effect


  The effect that the order of conditions has on the dependant variable
• Posttest Only Design


  A true experimental design in which the dependent variable in measured only once, after a manipulation of the independent variable
• Practice Effect


  When participants preform better over the course of a study simply because they are more experienced with the task
• Pretest-Posttest Design


  The dependant variable is measured both before and after manipulation of the independent variable
• Selection Differences


  Differences in the type of participants who make up each group in a between-subject experimental design
• Selective Attrition


  The loss of participants by way of individuals choosing to drop out of an experiment

  
  

  Mortality can also refer to how long a participant is in an experiment
• Within Subject Design


  The same participants experience all levels of the independent variable
• Confounding Variable


  Any variable that is not being measured and can influence the dependant and independent variables
• Solomon Four Group Design


  Group 1 is pre-test post-test with intervention

  Group 2 is pre-test post-test without intervention

  Group 3 is Post-test with intervention

  Group 4 is post-test without intervention
• Independent Group


  An experimental design where two groups are exposed to different conditions