Sampling

Question 1

What does ‘population’ refer to?

Answer 1

A large group of people who share specific characteristics that a researcher is interested in studying.

Question 2

What else is population referred to as?

Answer 2

Target population.

Question 3

What is a ‘sample’?

Answer 3

A smaller selection of people from our target population that are representative of the rest of the population.

Question 4

What is ‘bias’ (in terms of sampling)?

Answer 4

Under-representing or over-representing certain groups within the sample.

Question 5

What would be an example of bias within a sample?

Answer 5

• Too many younger people

- Too few males

Question 6

What is generalisation?

Answer 6

The extent to which the findings from a sample can be applied to the population.

Question 7

How is generalisation only possible?

Answer 7

If the sample is representative of the population.

Question 8

What are the five sampling techniques?

Answer 8

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

Question 9

What is opportunity sampling?

Answer 9

When people are selected who are willing and available to take part at the time (for example, approaching people in the street).

Question 10

What is an advantage of opportunity sampling? (PEEL)

Answer 10

• Quick, convenient and economical.
• This means that it doesn’t require as much planning and preparation as other sampling methods.
• For example, a study into stress levels during shopping can involve a researcher approaching shoppers rather than having to pre-identify participants.
• Strength: leads to fewer delays in the research process and less money spent.

Question 11

What is a disadvantage of opportunity sampling? (PEEL)

Answer 11

• Can be biased and unrepresentative.
• This means that the participants that are available at the time may not represent everyone in the target populations.
• For example, researchers may avoid people they do not like the look of (researcher bias); or if a study is conducted in the middle of a working day, the sample may only include people who work reduced hours or the unemployed and not full-time workers.
• Problem: sample may be biased and cannot be generalised to everyone, lowering external validity.

Question 12

What is volunteer sampling?

Answer 12

When people are selected that have put themselves forward to take part in the research.

Question 13

What is volunteer sampling also referred to as?

Answer 13

Self-selected sampling.

Question 14

What is an advantage of volunteer sampling? (PEEL)

Answer 14

• Quick, convenient and economical.
• This means that it doesn’t require as much planning and preparation as other sampling methods.
• For example, researchers can advertise for participants and people should begin to present themselves.
• Strength: fewer delays in the research process and less money spent.

Question 15

What is a disadvantage of volunteer sampling? (PEEL)

Answer 15

• Can be biased and unrepresentative.
• This means that volunteers tend to be a certain type of person.
• For example, they are more confident and motivated than most.
• Problem: sample may be biased (volunteer bias) and the findings cannot be generalised, therefore lowering external validity.

Question 16

What is systematic sampling?

Answer 16

When every Nth person is selected in the target population.
This can be done by getting a list of names from everyone in the target population and selecting ever 5th name (for example).

Question 17

What is an advantage of systematic sampling? (PEEL)

Answer 17

• Avoids researcher bias.
• This means that the researcher has no influence over who is chosen to be in there sample (randomisation).
• For example, picking whoever happens to be in the 5th position on an alphabetical list prevents researcher bias.
• Strength: the research is less biased, more objective, and less open to abuse or researcher influence.

Question 18

What is a disadvantage of systematic sampling? (PEEL)

Answer 18

• Not guaranteed to be representative.
• This means that, by chance, every nth name on a list could lead to only a certain type of person being selected.
• For example, every nth name could be male even though there are just as many females on the list; there can also still be an element of bias because the people at the beginning of the register and unlikely to be selected.
• Problem: findings cannot be generalised and lowers external validity.

Question 19

What is random sampling?

Answer 19

When the sample is selected through a random process and everyone in the target population has an equal chance of being selected.

Question 20

Give an example of how random sampling is done.

Answer 20

• Firstly, gathering a list of everyone within the population.
• Secondly, giving a number to every person on the list.
• Using a lottery method to pick the participants for the sample.

Question 21

What is an advantage of random sampling? (PEEL)

Answer 21

• Avoids researcher bias.
• This means that the researcher has no influence over who is selected for the sample.
• For example, picking names from a hat prevents the researcher from choosing people they think will help their hypothesis.
• Strength: random samples are less biased, more objective, and less open to abuse or researcher influence.

Question 22

What is a disadvantage of random sampling? (PEEL)

Answer 22

• Not guaranteed to be representative.
• This means that drawing names from a hat could by chance lead to only a certain type of person being selected.
• For example, every name drawn could be a male even though there are just as many females in the hat.
• Problem: findings cannot be generalised, lowering external validity.

Question 23

What is stratified sampling?

Answer 23

When the amount of people selected for the sample reflects the proportion of people in different subgroups according to their frequency within the population.

Question 24

Give an example of how stratified sampling can be done.

Answer 24

• Firstly, the researcher needs to identify the different subgroups within the population.
• Secondly, the researcher needs to work out the proportions needed to make the sample representative of the population.
• Lastly, the researcher selects the participants for the sample from each subgroup randomly.

Question 25

What is an advantage of stratified sampling? (PEEL)

Answer 25

• Highly representative.
• This means that it avoids researcher bias as well as ensuring that all subgroups are proportionally represented in the sample.
• For example, picking names from hats prevents researchers from choosing who they think will help their hypothesis as well as focusing on subgroups prevents ‘chance’ from representing all types of people.
• Strength: likely to be more representative than other sampling methods.

Question 26

What is a disadvantage of stratified sampling? (PEEL)

Answer 26

• Time-consuming and inconvenient.
• This means that it takes a great deal of planning to identify the subgroups and count frequencies within the subgroups before beginning the random selection process.
• For example, this level of planning is not needed for opportunity or volunteer sampling.
• Problem: more delays in the research process and more money spent.