*Sampling Methods

Question 1

What is a population in research?

Answer 1

Group of people

Focus of researchers’ interests, e.g., psychology students.

Question 2

What is random sampling?

Answer 2

All members have an equal chance of being selected

Obtain a complete list of all members of the population.

Question 3

What is a sample?

Answer 3

Smaller group drawn from population

Should be representative of the population.

Question 4

What are the strengths of random sampling?

Answer 4

• Potentially unbiased
• Confounding/extraneous variables should be divided between groups
• Increases internal validity

Question 5

What are the limitations of random sampling?

Answer 5

• Difficult
• Time-consuming
• Complete list of population may be difficult to obtain
• May not be representative
• Selected participants may refuse to take part

Question 6

What is systematic sampling?

Answer 6

Sampling frame is created by putting everyone in the population in order

Every nth number is selected, e.g., every 5th student on the register.

Question 7

What are the strengths of systematic sampling?

Answer 7

• Objective
• Research has no influence over who is selected

Question 8

What are the limitations of systematic sampling?

Answer 8

• Time-consuming
• Selected participants may refuse to take part

Question 9

What is stratified sampling?

Answer 9

Researcher identifies different subgroups (strata)

Sample reflects the proportions of that subgroup.

Question 10

What are the strengths of stratified sampling?

Answer 10

• Produces a representative sample
• Reflects the composition of the population
• Makes generalisation possible

Question 11

What are the limitations of stratified sampling?

Answer 11

• Cannot reflect all the ways that people are different
• Complete representation is not possible

Question 12

What is opportunity sampling?

Answer 12

Anyone who is available and willing

Anyone who is around at the time.

Question 13

What are the strengths of opportunity sampling?

Answer 13

• Convenient
• Cost-effective
• No list of population required
• No need to divide population into subgroups

Question 14

What are the limitations of opportunity sampling?

Answer 14

• Unrepresentative of population
• Cannot be generalised
• Researcher has complete control over who is selected

Question 15

What is volunteer sampling?

Answer 15

Participants select themselves

e.g., Advert in the newspaper or on a notice board.

Question 16

What are the strengths of volunteer sampling?

Answer 16

• Easy
• Minimum input from researcher
• Less time-consuming
• Participants are more engaged

Question 17

What are the limitations of volunteer sampling?

Answer 17

• Volunteer bias
• Attracting a certain kind of participant