Sampling

Question 1

What is a population in psychology research?

Answer 1

The group of people who are the focus of the researcher’s interest. (AO1)

Question 2

What is a sample in psychology research?

Answer 2

A group of people taken from the target population to take part in research, assumed to represent the population. (AO1)

Question 3

What is random sampling?

Answer 3

Every person in the target population has an equal chance of being selected. (AO1)

Question 4

How is random sampling conducted?

Answer 4

List all target population → write names on equal pieces of paper → pick the required number without looking. (AO1)

Question 5

Strength of random sampling?

Answer 5

Potentially unbiased → extraneous variables equally divided → ↑ internal validity. (AO3)

Question 6

Limitation of random sampling?

Answer 6

Time-consuming → difficult to collect all names → may not get participant consent. (AO3)

Question 7

What is systematic sampling?

Answer 7

Selecting participants using a system (e.g., every 5th person). (AO1)

Question 8

How is systematic sampling conducted?

Answer 8

Organise target population in a frame → apply system (e.g., every 5th person) until sample size is met. (AO1)

Question 9

Strength of systematic sampling?

Answer 9

Avoids researcher bias → objective selection → ↑ internal validity. (AO3)

Question 10

Limitation of systematic sampling?

Answer 10

Sample may not be fully representative → difficult to generalise → collecting names can be time-consuming. (AO3)

Question 11

What is stratified sampling?

Answer 11

Sample reflects the proportions of subgroups in the population (e.g., 70% female → 70% of sample female). (AO1)

Question 12

How is stratified sampling conducted?

Answer 12

Identify subgroups → calculate number for each proportion → select members using random sampling. (AO1)

Question 13

Strength of stratified sampling?

Answer 13

Most representative → accurately reflects population proportions → ↑ generalisability. (AO3)

Question 14

Limitation of stratified sampling?

Answer 14

Time-consuming → calculating proportions + random selection → may not get consent. (AO3)

Question 15

What is opportunity sampling?

Answer 15

Selecting participants who are available at a given time/place. (AO1)

Question 16

How is opportunity sampling conducted?

Answer 16

Go where the population is accessible → ask the first suitable participants to take part. (AO1)

Question 17

Strength of opportunity sampling?

Answer 17

Quick, easy, cheap → fewer resources required. (AO3)

Question 18

Limitation of opportunity sampling?

Answer 18

May not be representative → participants present at same time/place → similar personalities → ↓ generalisability. (AO3)

Question 19

What is volunteer (self-selected) sampling?

Answer 19

Participants volunteer themselves to take part (e.g., replying to an advert). (AO1)

Question 20

How is volunteer sampling conducted?

Answer 20

Place an advert where the target population can see it → wait for volunteers. (AO1)

Question 21

Strength of volunteer sampling?

Answer 21

Quick, easy, cheap → only need an advert to recruit participants. (AO3)

Question 22

Limitation of volunteer sampling?

Answer 22

May be biased → only certain personality types volunteer → ↓ generalisability. (AO3)