Sampling techniques

Question 1

Define population

Answer 1

Group of people researcher is interested in, that the sample is taken from.

Question 2

Define sample

Answer 2

The people who take part in the research

Question 3

Define bias in sampling

Answer 3

Some groups are over or underrepresented

Question 4

Define generalisation (population validity)

Answer 4

The extent to which we can apply the findings to the population. Made possible if the sample is representative of the population.

Question 5

What are the different types of sampling?

Answer 5

• Random sampling
• Systematic sampling
• Opportunity sampling
• Volunteer sampling
• Stratified sampling

Question 6

What is random sampling?

Answer 6

Every member of the target population has an equal chance of being selected for the sample. For example, picking names out of a hat, or using a random number generator.

Question 7

What is systematic sampling?

Answer 7

Every nth number of the target population is selected e.g. every 5th person on a register or every 8th house on a street.

Question 8

What is opportunity sampling?

Answer 8

The researcher selects participants from whoever is available at the time. For example, whoever happens to be in your class when you want to gather data.

Question 9

What is volunteer sampling?

Answer 9

Participants put themselves forward to be put into the sample. For example, Milgram asked for volunteers through a newspaper advertisement.

Question 10

What is stratified sampling?

Answer 10

The sample is a proportional representation of the target population. The target population is broken down into smaller groups, for example gender or age. You then sample from those groups (ideally randomly)

Question 11

What are the advantages of random sampling?

Answer 11

• unbiased collection, generalisable to the target population.
• no researcher bias as it’s a random sample

Question 12

What are the disadvantages of random sampling?

Answer 12

• unrealistic as it’s hard to get
  details of all members of the target population. This would be difficult to obtain and so is very difficult and time consuming to conduct
• Not always representative (e.g. all men could be randomly selected by chance, making it biased).

Question 13

What are the advantages of systematic sampling?

Answer 13

• No bias in collection as the researcher has no influence over who is chosen
• Results are likely to be representative of the target population (but not 100%) / everyone has an equal chance of being picked.

Question 14

What are the disadvantages of systematic sampling?

Answer 14

• Not 100% guaranteed to be representative as it could line up with some periodic traits or end up choosing all females for example. This would make the Sample less generalisable.

Question 15

What are the advantages of opportunity sampling?

Answer 15

• Easy to form as it involves eager, available participants

- Participants are engaged

Question 16

What are the disadvantages of opportunity sampling?

Answer 16

• Demand characteristics are probably higher as the participants are eager to satisfy the researcher.
• Biased Sample as again only specific types of people are likely to agree (unrepresentative).

Question 17

What are the advantages of volunteer sampling?

Answer 17

• Requires minimal input from the researcher and so it is less time-consuming.
• Ends up with participants who are more engaged.

Question 18

What are the disadvantages of volunteer sampling?

Answer 18

• Unrepresentative as usually only particular types of people volunteer to participate (e.g. confident, extroverts). So Sample is likely to be biased.

Question 19

What are the advantages of stratified sampling?

Answer 19

Genuinely representative & random

Question 20

What are the disadvantages of stratified sampling?

Answer 20

Time-consuming.