experimental design

Question 1

what is an experimental design?

Answer 1

• how p’s are used in experiments
- how they are allocated/arranged to different experimental conditions

Question 2

what are the types of experimental design?

Answer 2

1) independent groups
2) repeated measures
3) matched pairs

Question 3

what is an independent group design?

Answer 3

• different p’s are used in each of the conditions
- they only complete one level of IV
- experimental or control condition
• p’s are randomly allocated to each condition to try and balance out any differences (p’s variables)
• results from the two groups are compared

Question 4

what are the repeated measures design?

Answer 4

• all p’s take part in both conditions/levels of the IV
- they could complete the experimental and control condition
• their two means scores (from both conditions) are then compared to see if there was a difference

Question 5

what is a limitation of repeated measures design?

Answer 5

• demand characteristics
• p’s get bored
• p’s can get better

Question 6

what is the counterbalancing (ABBA)?

Answer 6

• all p’s take part in both conditions
- but split into different halves and experience in different orders
- eg: group 1 do a>b, group 2 do b>a
- order effects are balanced out but not removed/prevented

Question 7

what is a matched p’s design?

Answer 7

• different but similar p’s are used in each on the conditions
• p’s are matched across the groups of any characteristics judged to be important for that particular study
• example:
- age, personality, gender, IQ
• a pilot study (pre test) should be done for effective matching

Question 8

what are the + and - of independent design?

Answer 8

(+)
• randomly allocated
• less likely to have demand characteristics
• no order effects

(-)
• participant variables (EV)
- minimised
• larger sample
- need to recruit more p’s

Question 9

what are the + and - of repeated measures design?

Answer 9

(+)
• same p’s
- easier to compare
- no p’s variables
• smaller sample in total
• time consuming
- leave time between

(-)
• demand characteristics can be shown as p’s start to catch onto the aim
• boredom
- p’s show no effort effecting results
• order effect
- minimises with ABBA
• p’s can get better as the experiment repeats

Question 10

what are the + and - of matched p’s design?

Answer 10

(+)
• no ordered effects
• less demand characteristics

(-)
• p’s variables
- minimised
- matched not perfect
• time consuming