design

• what is design?


  how participants are allocated to each condition
• what is independent groups?


  This is where participants do one of the experimental conditions
• what is matched pairs?


  This is where participants won’t experimental condition, but the participants first matched and put into pairs based on important characteristics (like gender or intelligence something that is believed to be an extraneous variable) one person from each pairs randomly allocated to one experimental condition and the other person in the pair joins the other
• what is repeated measures?


  The participants do experimental conditions
• what are order effects?


  A consequence of participants doing all the conditions the order that they do the conditions might affect that performance in the second condition not the manipulation of the independent variable
• What is the practice effect?


  Participants may become practice at the test so their performance will improve
• What is the fatigue effect?


  Participants may become tired of the test so that performance would deteriorate
• What are the advantages of independent groups?


  No order effects because the participants take part in the experiments once This increases the internal validity of the findings

  Viewer demand characteristics as they only take part experiment once they are less likely to guess the aim of the study
• what are the disadvantages of independent groups?

  Economical twice the number of participants needed compared to repeated measures design makes it less practical

  There can be participant extraneous variables because there could be individual differences between groups which makes it harder to establish cause effects
• which two types of design are similar?


  The match design is essentially an independent group design with the more control of participant extraneous variables
• what are the advantages of match pairs?


  It has no order effect, which means fewer demand characteristics

  an attempt has been made to control extraneous variables because participants first put into pairs in terms of a factor that might also impact the dependent variable but it’s not the dependent variable. This means that each experimental condition has similar types of people in it so participant extraneous variables are reduce hence increasing internal validity.
• what are the disadvantages of match pairs?


  It is less economical because it takes time and effort to 1st screen people on potential independent variables and match them in pairs and then randomly allocate one from each pair to each condition

  It is also less economical
• what are the advantages of repeated measures?


  Participant extraneous variables are controlled as the participants in each condition for a repeated measure design and the same so they’ll be no individual differences. This means that the experiment could be more confident that change in the dependent variable is due to the manipulation of the independent variable increasing the internal validity.

  It is more economical because the number of participants are needed compared to repeated measures
• What are disadvantages of repeated measures?


  Order effects because the performance in the second condition might not be due to the minute of the independent variable but maybe due to it being the second time they have done the study this reduces the internal validity of the findings

  demand characteristics because part is complete all of the conditions for the experiment they may guess the three of the study and change their behaviour accordingly they could try to please experiment or sabotage the study (screw yffect