Experimental Design

Question 1

What are the 2 conditions in an experiment?

Answer 1

Experimental and control conditions

Question 2

In an experiment, the researcher must decide how to split participants between the experimental and control groups, what are the 3 methods of doing this?

Answer 2

1. Independent groups
2. Repeated measures
3. Matched pps/pairs

Question 3

What is independent groups?

Answer 3

Tests the two different conditions on two different groups of people - random allocation

Question 4

What are the strengths and weaknesses of independent groups?

Answer 4

Strengths
+Less chance of order effects, like learning or fatigue
+Can use the same stimulus material
+No order effects
Weaknesses
-Less effective for controlling participant variables such as individual differences
-requires more pps

Question 5

What is repeated measures?

Answer 5

The different conditions of the experiment are performed on the same group of people

Question 6

What are the strengths and weaknesses of Repeated measures?

Answer 6

+Participant variables eliminates (Weakness of IG)
+Fewer pps need to be found (W of IG)

• Order effects, like fatigue and learning occur (S of IG)
• Demand characteristics due to more contact with researcher
• Cannot use same stimulus material due to order effects (S of IG)

Question 7

What can be done to manipulate repeated measure in order to reduce order effects?

Answer 7

pps can be counter balanced - half do condition 1 then condition 2, the other half do 2 then 1

Question 8

What does counter balancing repeated measures do and how do you do it?

Answer 8

+reduces order effects

half do condition 1 then condition 2, the other half do 2 then 1

Question 9

What is matched pairs?

Answer 9

participants in one group are matched to participants in the other group for traits like age gender and ability - like twins!

Question 10

What are the strengths and weaknesses of matched pairs?

Answer 10

Strengths
+pps variation is reduced
+no order effects

Weaknesses

• costly
• time consuming
• need more pps (than repeated measures)

Question 11

What is a Pilot study?

Answer 11

A small scale replication of a study - they are carried out to check the design and implementation of the main study

Question 12

The selection of participants must reflect the what?

Answer 12

Target population

Question 13

What is a target population?

Answer 13

A group of people who share a given set of characteristics about which the researcher wishes to draw a conclusion e.g. A level students

Question 14

As the target population is normally too large, what does the researcher need to obtain?

Answer 14

A representative sample

Question 15

What must the people in a representative sample posses?

Answer 15

Similar characteristics to the target population

Question 16

What are the 3 methods of participant sampling?

Answer 16

Opportunity
Random
Volunteer

Question 17

What is opportunity sampling?

Answer 17

Most easily available

Biased because its drawn from a small section of the population

Question 18

Volunteer sample

Answer 18

relies on people responding to adverts etc

Biased because it only attracts those from areas of advert - e.g. those who read the same type of newspaper/magazine

Question 19

What is random sampling?

Answer 19

Produces the ideal sample because every member of the target population has an equal chance of being picked to be in the sample

Question 20

What are observational studies?

Answer 20

are investigations where the researcher observes a situation and records what happens but does not manipulate an independent variable.

Observational studies therefore tend to be high in ecological validity as there is no intervention and if the observer remains undetected the method avoids problems with demand characteristics.

Question 21

(Observational designs) What are time interval, time point and event sampling?

Answer 21

Time interval sampling: breaking down the observation into small, equally sized, time intervals and judging whether the operationalized behaviour occurs during each interval.
Time point sampling: involves selecting specific “points” at which to collect specific data. Information about those points can then be used to say something about a phenomena over a broader area.
Event sampling: Event sampling consists of the researcher recoding an event every time it happens. For example, ticking a box every time somebody picks their nose. Although behaviours should not be missed as in time sampling, if too many observations happen at once it may be difficult to record everything.

Question 22

How are variables operationalized?

Answer 22

Operationalization is the process of strictly defining variables into measurable factors. The process defines general concepts and allows them to be measured, empirically and quantitatively.