experimental/research design

Question 1

what is an independent groups design?

Answer 1

experimental design where different participants are used in each condition of the independent variable

Question 2

strengths of using an independent groups design

Answer 2

• avoids order effects (such as practice or fatigue) as people participate in one condition only - less likely to get better/worse
• demand characteristics are eliminated - participants are less likely to guess the aims of the study as pp only perform one task, increasing validity

Question 3

weaknesses of using an independent groups design

Answer 3

• More people are needed for the same amount of data than with the repeated measures design - more time-consuming and costly
• participant variables between the conditions is a problem as the pps only take part in one condition therefore reduce validity

Question 4

control for independent groups

Answer 4

to control pp variables - after the pps have been recruited, they should be randomly assigned to their groups. This should ensure the groups are similar, on average.

Question 5

what is a repeated measures design?

Answer 5

experimental design where the same participants participate in each independent variable condition

means that each experiment condition includes the same group of pps

Question 6

what are the strengths of using a repeated measures design?

Answer 6

• as the same participants are used in each condition, participant variables (i.e., individual differences) are reduced
• fewer people are needed as they participate in all conditions (i.e., saves time)

Question 7

what are the weaknesses of using a repeated measures design?

Answer 7

• order effects - refer to the order of the conditions affecting the participants’ behavior. Performance in the second condition may be better because the participants know what to do (i.e. practice effect). Or their performance might be worse in the second condition because they are tired (i.e. fatigue effect). = affects validity
• demand characteristics - the first test could induce demand characteristics because it allows participants to guess the survey’s target when it is repeated in the second test. There is a risk that participants will change some aspect of their behaviour in response to knowing the research hypothesis = may reduce research validity.

Question 8

control for repeated measures

Answer 8

counterbalancing -

Question 9

what is a matched pairs design?

Answer 9

• where pairs of participants are matched in terms of important characteristics/variables, such as age or socioeconomic status
• one member of each pair is then placed into the experimental group and the other member into the control group

Question 10

what are strengths of the matched pairs design?

Answer 10

• reduces participant variables because the researcher has tried to pair up the participants so that each condition has people with similar abilities and characteristics
• no order effects as participants only take part in one condition

Question 11

what are the weaknesses of a matched pairs design?

Answer 11

• requires a big sample - needs twice as many participants as a repeated measures design - time consuming and costly
• not practical - impossible to match people exactly unless they are identical twins and factors like tiredness or motivation can still affect the results

Question 12

control for matched pairs