4.2.3.1 SAMPLING

Question 1

what is sampling?

Answer 1

• the process of selecting a representative group from the population the research is investigating

Question 2

what is the purpose of sampling?

Answer 2

• so we can generalise from the sample to the target population
• the more representative the sample, the more confident the researcher can be that the results can be generalised to the target population

Question 3

what is a population?

Answer 3

• large group of individuals who the researcher may be interested in studying

Question 4

what’s a target population?

Answer 4

• the total group of individuals selected from the population the research is investigating
• desired sub-group of the population to be studied

Question 5

what’s a sample?

Answer 5

• group of people who take part in the research
  -> they’re drawn from the target population
• it’s presumed to be representative of the population
• this avoids generalisation and means all participants have an equal chance of being selected

Question 6

how is random sampling selected?

Answer 6

• type of probability sampling where everyone in the entire target population has an equal chance of being selected
• require a way of naming / numbering the target population and then using some type of raffle method to choose those to make up the sample
• best method of selecting your sample from the population of interest

Question 7

what are 2 advantages of random sampling?

Answer 7

1) unbiased selection
-> more likely to be a representative sample

2) results are able to be generalised to the target population
-> as results are fairly representative

Question 8

what are 2 disadvantages of random sampling?

Answer 8

1) time consuming and impractical
-> not always a possibility to be able to have all the info on a target population
-> / for all the target population to want to take part in the study

2) could be non-representative
-> all of one gender could be randomly selected
-> wouldn’t be a true example of the target population

Question 9

how is systematic sampling selected ?

Answer 9

• chooses subjects in a systematic way from the target population
  -> every nth ppt on a list of names

to take a systematic sample
- you list all the members of the population
- decide upon a sample you’d like
- divide the number of people in the population by the number of people you want in your sample
-> you get the nth number

• by taking every nth name, you get a systematic sample of the correct size

Question 10

what are 2 advantages of systematic sampling?

Answer 10

1) unbiased selection
-> meaning it’s more likely to be a representative sample

2) results should be generalisable to the target population
-> as a result of them being representative

Question 11

what are 3 disadvantages of systematic sampling?

Answer 11

1) not always truly random
-> the selection process can interact with a hidden periodic trait

2) may be non-representative
-> all of one gender could be selected randomly
-> therefore not a true example of the target population

3) it’s very difficult to achieve
-> ie. time, effort, money

Question 12

how is stratified sampling selected?

Answer 12

• small-scale reproduction of the target population
• the researcher divides and categorises the population by characteristics important to the research
  -> a list is made of each variable which might have an effect on the research
• population is sampled within each category
  ie) if the whole population has 18% of ppl who are male, aged 30-40
  the representative sample will have 18% of ppl who are male, aged 30-40

Question 13

what are 2 advantages of stratified sampling?

Answer 13

1) sample should be highly representative of the target population
-> we can generalise from the results obtained

2) selection is unbiased as it’s based on the sub groups in society

Question 14

what are 2 disadvantages of stratified sampling?

Answer 14

1) time consuming
-> gathering a sample would be long and difficult

2) researcher requires knowledge of the subgroups and categories of the population
-> may not be available

Question 15

how is opportunity sampling selected?

Answer 15

• uses people from target population available at the time and willing to take part
• based on convenience
• opportunity sample is obtained by asking members of the population of interest, if they’d like to take part

Question 16

what are 2 advantages of opportunity sampling?

Answer 16

1) natural experiments
-> use opportunity sampling as the researcher has no control over who’s being studied

2) quick and easy way of choosing participants + information

Question 17

what are three disadvantages of opportunity sampling?

Answer 17

1) cannot generalise
-> sample is likely to be unrepresentative
-> likely to miss whole sections of the population

2) self selected sample
-> ppts have the option to disagree/agree to join at the time of the study

3) could be biased

Question 18

how is volunteer sampling selected?

Answer 18

• people volunteer to take part
• selecting themselves as ppts of a study by replying to adverts

Question 19

what are 3 advantages of volunteer sampling?

Answer 19

1) variety of participants
-> they’re choosing to take part

2) easy way to get into
-> ppl are wiling to be involved

3) less likely to have ppl who want to jeopardise the study

Question 20

what are 2 limitations of volunteer sampling?

Answer 20

1) volunteer bias
-> results won’t be able to be generalised as volunteers are often ‘certain’ types of ppl

2) demand characteristics
-> volunteers are often eager to please which results in DC
-> they’ll behave how they think the researcher wants them to

Question 21

what is a biased sample?

Answer 21

• when certain groups are over / under represented within the sample selected
• limits how much the findings of the study can be generalised to the whole population

Question 22

what is generalisability?

Answer 22

• refers to the extent to which we can apply the findings of our research to the population
• can only occur if the sample of ppts is representative of the population