Sampling methods

Question 1

Bias

Answer 1

A systematic distortion.

Question 2

Generalisation

Answer 2

Applying the findings of a particular study to the target population.

Question 3

Target population

Answer 3

The group of people the researcher is interested in.

Question 4

Sampling frame

Answer 4

A smaller group taken from the target population from which the psychologist will select their sample, with the hope that the same will be representative of the target population.

Question 5

Sampling

Answer 5

The process of selecting participants from the sampling frame with the aim of producing a sample that is representative of the group in society.

Question 6

Opportunity sampling

Answer 6

The sampling technique most used by psychology students.
It consists of taking a sample from people who are available at the time that the study is carried out and fits the criteria that you are looking for.

Question 7

Opportunity sampling - advantage

Answer 7

Easiest method.
You just use the first suitable participants you can find which means it takes less time to locate your sample.

Question 8

Opportunity sampling - disadvantage

Answer 8

Inevitably biased because the sample is drawn from a small part of your target population.

Question 9

Random sampling

Answer 9

This is a sampling technique which is defined as a sample in which every member of the target population has an equal chance of being chosen.
This involves identifying everyone in the target population and then selecting the number of participants you need in a way that gives everyone an equal chance of being selected.

Question 10

Random sampling - disadvantage

Answer 10

Need to have a list of all members of the target population and then contact all of those selected, which may take some time.

Question 11

Random sampling - advantage

Answer 11

Unbiased; all members of the target population have an equal chance of selection.

Question 12

Snowball sampling

Answer 12

Current participants recruit further participants from people they know.
Relies on referrals from initial participants.

Question 13

Snowball sampling - advantage

Answer 13

Enables a researcher to locate groups of people who are difficult to access.

Question 14

Snowball sampling - disadvantage

Answer 14

The sample is not likely to be a good cross-section from the population because its friends of friends.

Question 15

Self-selected sampling

Answer 15

Self-selected (or volunteer sampling) consists of participants becoming part of a study because they volunteer when asked or in response to an advert.

Question 16

Self-selected sampling - advantage

Answer 16

Gives access to a variety of participants which may make the sample more representative and less biased.

Question 17

Self-selected sampling - disadvantage

Answer 17

Sample is biased in other ways because participants are likely to be more highly motivated to be helpful, and/or with extra time on their hands.
This results in a volunteer bias.

Question 18

Systematic sampling

Answer 18

Using a predetermined system with a target population.
For example:
Participants are selected at fixed intervals (e.g. every fifth).

Question 19

Systematic sampling - advantage

Answer 19

Unbiased as participants are selected using an objective system.

Question 20

Systematic sampling - disadvantage

Answer 20

Not truly unbiased/random unless you select a number using a random method and start with this person, and then select every nth person.

Question 21

Stratified / quota sampling

Answer 21

Stratified sampling involves classifying the population into categories and then when the proportions have been identified, choosing a sample through a random sample which consists of participants from each category in the same proportions as they are in the population.

Question 22

Stratified sampling - advantage

Answer 22

Likely to be more representative than other methods because there is a proportional representative of subgroups.

Question 23

Stratified sampling - disadvantage

Answer 23

Very time-consuming to identify subgroups and then select participants and contact them.