Sampling techniques

Question 1

What is Sampling?

Answer 1

Sampling means selecting the group that you will actually collect data from in your research.

Question 2

What are participants?

Answer 2

People who take part in the research.
It is important to use suitable participants in a study

Question 3

What is the target population?

Answer 3

The target population is the group of people from whom the sample is drawn.

Question 4

Why do we use sampling techniques?

Answer 4

It is impossible to study every single person in a target population so we use sampling techniques to select a sample or sub-group of the population that is likely to be representative of the entire target population that we are interested in.
If the sample we select is going to represent the target population then we need to make sure that the people in it are similar to the other members of the target population.

Question 5

Why must samples be representative?

Answer 5

If your sample is representative, you can then generalise the results of the study to the wider population

Question 6

What are the different sampling techniques?
(there are 6 of them)

Answer 6

Random
Systematic
Stratified
Snowball
Opportunity
Self-selected

Question 7

What is random sampling?

Answer 7

Everyone in the entire target population has an equal chance of being selected.
This is similar to the national lottery.
Random samples require a way of naming or numbering the target population and then using some type of raffle method to choose those who will make up the sample.

Question 8

Give an advantage of random sampling?

Answer 8

The advantages are that your sample will represent the target population and eliminate sampling bias

Question 9

Give a disadvantage of random sampling?

Answer 9

it is very difficult to achieve (due to: time, effort and money).

Question 10

What is systematic sampling?

Answer 10

Systematic sampling is a probability sampling method where researchers select members of the population at a regular interval – for example, by selecting every 15th person on a list of the population.

Question 11

Give an advantage of systematic sampling?

Answer 11

It reduces the potential for bias

It is simple and convenient to use.

Question 12

Give a disadvantage of systematic sampling?

Answer 12

Patterns Can Be Predicted

Unequal Selection is Possible

Question 13

What is Stratified sampling?

Answer 13

Classifying the target population into categories, then choosing a sample that is in the same proportion as the population

Question 14

Whats an advantage of stratified sampling?

Answer 14

More cost-effective
Prevents sample bias
More accurate data

Question 15

What’s a disadvantage of stratified sampling?

Answer 15

Difficult data analysis
Requires more planning
Lacks versatility (only works for surveys)

Question 16

What is snowball sampling?

Answer 16

Snowball sampling can be used if your population is not easy to contact.
You may ask a participant who fits your target population to tell their friends about the study and ask them to get in touch with you, when youll ask them to take the survey as well.

Question 17

Whats an advantage of snowball sampling?

Answer 17

Cost effective
Gathers participants quickly

Question 18

Give some disadvantages of the snowball sampling

Answer 18

Sample may not be representative of the entire target population. The researcher has no idea of the true distribution of the population and of the sample.

Sampling bias could occur because initial subjects tend to nominate people that they know well, who may have similar traits and charcteristics to the researcher, so the sample that the researcher will obtain is only a small subgroup of the entire population.

Question 19

What is opportunity sampling?

Answer 19

Uses people from target population available at the time and willing to take part.
It is based on convenience.
An opportunity sample is obtained by asking members of the population of interest if they would take part in your research. An example would be selecting a sample of students in the common room.

Question 20

Whats an advantage of opportunity sampling?

Answer 20

This is a quick and easy way of choosing participants

Question 21

Whats a disadvantage of opportunity sampling?

Answer 21

sample population may not be representative of the target population, and could be biased

Question 22

Whats Self Selected Sampling?

Answer 22

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

Question 23

Give an advantage of Self Selected Sampling

Answer 23

it is quick and relatively easy to do.
It can also reach a wide variety of participants.

Question 24

Give a disadvantage of Self Selected Sampling?

Answer 24

They are self selected, so sample may not be representative of the entire target population.

Question 25

How many recruits do I need?

Answer 25

This depends on several factors; the size of the target population is important. If the target population is very large (e.g. all 4-6 yr olds in Britain) then you need a fairly large sample in order to be representative.
If the target population is much smaller, then the sample can be smaller but still be representative.

Question 26

What is a sample?

Answer 26

A sample is a subset of individuals from a larger population.