RESEARCH METHODS: experimental design

Question 1

what are the two conditions in an experiment?

Answer 1

experimental condition and control condition

Question 2

what is an experimental condition?

Answer 2

where you manipulate a variable to see the effect

Question 3

what is a control condition?

Answer 3

where nothing is manipulated so that we have a base line to compare our results with

Question 4

what is the experimental design?

Answer 4

refers to how participants are allocated to the different conditions in an experiment.

Question 5

what are the 3 types of experimental designs?

Answer 5

1. independant measures design
2. repeated measures design
3. matched pairs design

Question 6

what is the independant measures design?

Answer 6

1. Recruit a group of participants and divide them into two groups
2. group 1 does experimental task with the independant variable set for condition 1
3. group 2 does experiment task with the independant variable set for condition 2
4. measure the DV for each group and compare the results for the two groups

Question 7

what is a repeated measures design?

Answer 7

when each participant will experience both conditions.
compare the results of both conditions

Question 8

what is a matched pairs design?

Answer 8

Pairs of participants are grouped in terms of key variables.
then one member is assigned to condition A and the other is assigned to condition B
compare the results for the matched pairs

Question 9

evaluate the independant group design

Answer 9

+ order effects are not a problem. Participants are less likely to guess the aims

• participants are not the same in terms of participant variables
• if a researcher finds a mean difference in the DV, it is more to do with the participant variables. These differences are confounding variable.
• decreases the validity of the finding

TO DEAL WITH THIS PROBLEM: researches use random allocation to ensure that groups are not biased on key variables

Question 10

evaluate the repeated measures design

Answer 10

+ participants variables are controlled therefore there is a higher a validity and fewer participants needed.
+ less time is spent on recruiting them

• twice as many participants would be needed to produce equivalent data which increases time and money spent on recruiting participants
• participants have to do at least two tasks and the order of these tasks may be significant.
  TO DEAL WITH THIS PROBLEM: counterbalancing is used to mix up order of tasks.
• demand characteristics are a feature of repeated measures design than independant group design.
• order effects also arise because repeating two tasks can cause boredom or fatigue that may lead to deterioration of performance. so it matters what order the tasks are used…
  HOWEVER
  COUNTER ARGUMENT:
  + participant performance may improve through the effects of practice especially on a skills based task. So participants will perform better on the second task.

Question 11

evaluate the matched pairs design

Answer 11

+ participants only take part in single conditions so demand charactersitics are less of a problem
+ some attempts to reduce participant variables.
COUNTER - participants can never really be matched

• matching may be time consuming = expensive particularly when a pre-test is requires.
  so it is less economical.