Experimental Design

Question 1

what is experimental design?

Answer 1

way in which participants are used in experiments - do they take part in all conditions or just one

Question 2

what is independent groups design?

Answer 2

an experimental design whereby two groups are exposed to different experimental conditions

Question 3

how does independent groups design work?

Answer 3

• recruit a group of participants
• randomly divide them in 2 so you have two different groups of participants
• one group does
  condition 1
• the other group does condition 2
• measure the DV for each group and compare

Question 4

what is repeated measures design?

Answer 4

an experimental design where the same participants take part in each condition of the experiment

Question 5

how does repeated measures work?

Answer 5

• recruit a group of participants
• whole group does condition one
• whole group then does condition two
• measure the DV for each and compare

Question 5

how does matched pairs work?

Answer 5

• recruit a group of participants
• ask them to complete a questionnaire and then match them in pairs for similar traits
• person A of each pair completes condition 1
• person B of each pair completes condition 2
• compare the results for the matched pairs in each condition

Question 5

what is matched pairs design?

Answer 5

an experimental design where pairs of participants are matched in terms of key variables, such as age and IQ

Question 5

disadvantages of independent groups

Answer 5

• individual differences could affect the results (e.g. different abilities/characteristics of the participants)
• more participants are required to take part in the experiment

Question 5

advantages of independent groups

Answer 5

• no order effects as they only complete 1 condition
• no demand characteristics as the participants don’t see the entire experiment

Question 6

advantages of repeated measures

Answer 6

• using same person across all conditions of the experiment means there will be no problems with individual differences
• as one person does all the conditions fewer people have to be found

Question 7

disadvantages of repeated measures

Answer 7

• likely to be order effects as participants may improve with each condition (practice effects) or get worse (boredom & tiredness) - can try to avoid order effects through counterbalancing
• person might guess what study is about - could be demand characteristics

Question 8

advantages of matched pairs

Answer 8

• no order effects as different people are used in each experimental condition
• demand characteristics less likely as different people are used in each experimental condition
• comparisons can be easily made between the members of the pair

Question 9

disadvantages of matched pairs

Answer 9

• some individual differences and participant variables may still occur
• require more participants for this type of experimental design
• time consuming to gather the info required to match pairs correctly