sampling

Question 1

what is opportunity sampling ?

Answer 1

• selecting a sample from whoever is willing and available at the time of selection

Question 2

strengths of opportunity sampling

Answer 2

• tends to be more ethical as the researcher can judge if the participant is likely to be upset by the study or too busy to take part
• the researcher has more control over who is asked so finding participants should be quick and efficient and costs less money
• one of the easiest ways of getting a sample of participants

Question 3

limitations of opportunity sampling

Answer 3

• more chance of bias as researcher may have more control over who is chosen and choose certain people leading to a biased sample
• those that are picked are available and willing to take part and this will rule out any body that is not willing to take part or unavailable at the time
• culture bias as all participants would be from the same area

Question 4

what is random sampling ?

Answer 4

• here every member of the target population has an equal chance of being selected
• a complete list of all members of the target population is obtained and a sample is then selected from the full list in a random way

Question 5

strengths of random sampling

Answer 5

• no researcher bias in the way participants are selected and everyone has a equal chance of being selected so therefore the sample is likely to be representative of the target population

Question 6

limitations of random sampling

Answer 6

• can be time consuming and often impossible to carry out especially when you have a large population
• if a participant does not wish to take part the whole sample has to be re selected otherwise the sample is no longer truly random

Question 7

what is stratified sampling ?

Answer 7

• reflects the proportion of the people in the target population and this is done by :
• classifying the population into categories ( strata ) , participants obtained from each group in proportion to their occurence in the target population and this is done by random selection

Question 8

strengths of stratified sampling

Answer 8

• efficient in ensuring that there is representation in each group
• allows researchers to include a proportional sample of each subgroup in the population without needing to sample large numbers overall

Question 9

limitations of stratified sampling

Answer 9

• time consuming as categories have to be identified and calculated
• if you do not have details of all people in your target population you would struggle to conduct this sample

Question 10

what is systematic sampling

Answer 10

• uses a predetermined system to select participants ( every nth member of the target population)

Question 11

strengths of systematic sampling

Answer 11

• avoid bias as once the researcher has decided what number they are going to use in selection they have no control over who is selected
• fairly simple procedure
• the law of probability says that researcher will normally get a representative sample

Question 12

limitations of systematic sampling

Answer 12

• small chance that an unusual sample could be chosen which might not accurately represent the whole population
• it is not as objective as random sampling as the researcher may decide on how people are listed before selection

Question 13

what is volunteer sampling ?

Answer 13

• participants selecting themselves to be part of the sample

Question 14

strengths of volunteer sampling

Answer 14

• easy and requires minimal input from the researcher so less time consuming than others forms of sampling
• may be higher engagement from the participants during study as they have read the details of the study and are willing to take part

Question 15

limitations of volunteer sampling

Answer 15

• volunteer bias is a problem ( asking for volunteers may attract a certain “profile” of person who is helpful , keen and curious which may effect findings and can be generalised)
• sample may be unrepresentative if only conducted in one place