Variables & Experimental Methods

Question 1

Define ‘variable’.

Answer 1

A variable refers to anything that varies.

Question 2

Define the term ‘independent variable’.

Answer 2

The variable the researcher manipulates.

Question 3

Define the term ‘dependent variable’.

Answer 3

The variable that is measured.

Question 4

What are the key features that make a ‘true experiment’?

Answer 4

Manipulation of an independent variable.
Randomisation.
Control.

Question 5

What is meant by ‘manipulation of an independent variable’?

Answer 5

The independent variable is directly manipulated by the researcher to produce a change in the dependent variable.

Question 6

What is meant by ‘randomisation’?

Answer 6

The participants are randomly allocated to a condition/ participants take part in each condition of the IV.

Question 7

What is meant by ‘control’?

Answer 7

Efforts are made to control all variables other than the IV and the DV in an experiment. These variables are known as ‘extraneous variables’.

Question 8

What is the aim of controlling extraneous variables?

Answer 8

To minimise their possible impact on the results of the investigation.

Question 9

What are the types of experimental method?

Answer 9

Lab
Field
Natural
Quasi

Question 10

Describe laboratory experiment.

Answer 10

• Is conducted in a controlled environment.
• IV is directly manipulated by the researcher and the effect on the DV is measured.
• Participants are aware that they are in the study, however may not know the true aim of it.
• It is possible to establish cause and effect due to the controlled environment and direct manipulation of the IV.

Question 11

Describe field experiment.

Answer 11

• Carried outside of the lab.
• IV is directly manipulated by the researcher.
• Participants usually unaware that they are in the experiment, so behaviours are natural.
• Difficult to control extraneous and possible confounding variables.

Question 12

Describe natural experiment.

Answer 12

• IV has not been directly manipulated by the researcher.
• Researcher takes advantage of a naturally occurring IV.
• Tend to use this type of experiment when there are practical or ethical difficulties with manipulating the IV.
• Environment doesn’t necessarily have to be natural.
• Participants are not randomly allocated to conditions.

Question 13

Define quasi- experiment.

Answer 13

• Iv is naturally occurring.
• IV is not made to vary, it is a difference between people that exists (age, gender).
• Means ‘almost and experiment’.
• IV is a condition that exists.
• Environment doesn’t have to be natural.
• Casual conclusions can only be drawn.

Question 14

What are some advantages of a lab experiment?

Answer 14

• Makes a true experiment.
• High level of control allows establishment of cause and effect.
• Randomly allocated when put into groups.
• No bias involved.

Question 15

What are some disadvantages of a lab experiment?

Answer 15

• Not taken place in a natural setting, so participants could alter their behaviour.
• Therefore lacks validity.

Question 16

What are some advantages of a field experiment?

Answer 16

• Participants behaviour won’t be altered as it takes place in a natural setting.
• Generally more accurate results.

Question 17

What are some disadvantages of a field experiment?

Answer 17

• Could be unethical due to participants being unaware that they are in the study.
• Less control over other variables.

Question 18

What are some advantages of natural and quasi experiments?

Answer 18

• Takes advantage of naturally occurring independent variables.
• Is the most ethical type of experiment.

Question 19

What are some disadvantages of natural and quasi experiments?

Answer 19

• Very low levels of control over the variables, so have to be careful drawing conclusions.
• Findings may not be generalised.
• Can only draw casual conclusions.