Lesson 7- Experimental Design

Question 1

What is an experimental design?

Answer 1

An experimental design of a study is how the participants are allocated different conditions.

Question 2

What are the three types of experimental designs?

Answer 2

-Independent groups
-Repeated meausres
-Matched pairs

Question 3

What are independent groups?

Answer 3

A type of experimental method in which different participants are used in two or more DIFFERENT conditions
- Participants are randomly allocated to each condition (this is in order to avoid research bias)

Question 4

What type of data does independent groups produce?

Answer 4

It produces unrelated data.
(Data where the individual data points in one condition cannot be paired with any of the data points within the other condition.

Question 5

What are order effects?

Answer 5

When the sequence in which participants take part in conditions influences their performance or behaviour

Question 6

What are the 3 advantages of independent groups?

Answer 6

1. Order effects will not occur as there are different participants in each condition
2. The chance of DEMAND CHARACTERISTICS are reduced as participants only do one condition each and so have less chance to guess the purpose of the study

3.The same task/materials can be used in both conditions as participants are always naive to the task

Question 7

What are the 2 disadvantages of independent groups?

Answer 7

1. More participants are needed for this experimental design
2. There is always a chance that the different results between the two conditions are due to PARTICIPANT variables rather than manipulation of the INDEPENDENT VARIABLE

Question 8

What are repeated measures?

Answer 8

A type of experimental design where the same participants complete in each of the two (or more) experimental conditions

Question 9

What are the advantages of repeated measures design?

Answer 9

1. As the same people are measured in all conditions there are no PARTICIPANT VARIABLES between conditions
2. Half as many participants are needed compared to an independent groups design

Question 10

What are the disadvantages of a repeated measures design?

Answer 10

1. Order effects may affect the results (This can be overcome by COUNTERBALANCING)
2. Demand characteristics are more likely to occur as participants are involved in the entire study
3. This experimental design takes more time, especially if a time gap between the different conditions is required.

Question 11

How does counterbalancing reduce the impact of order effects?

Answer 11

–It reduces the impact of order effects by reversing the order each participant completes the condition.

For example, by having half of the participants do condition A first and then condition B second, whilst the other half do condition B first and condition A second.

Question 12

What is a matched pair design?

Answer 12

A type of experimental design where pairs of participants are matched in terms of key CHARACTERISTICS, such as age and IQ.

One member of each pair is then allocated into both experimental conditions

Question 13

What are the 3 advantages of a matched pair design?

Answer 13

1. Less risk of order effects

2.Less risk of demand characteristics

3. Participant variables are unlikely as the groups have been closely matched

Question 14

What are the 3 disadvantages of matched pair design?

Answer 14

1. Twice as many paritcipants are requires compared with a repeated measure design
2. The matching process can be difficult, as ntwo individuals are the exact same as one another

3.The matching process is time consuming