sampling

Question 1

what are the 5 sampling methods

Answer 1

stratified
systematic
random
opportunity
volunteer

Question 2

what is stratified sampling

Answer 2

researchers divide subjects into subgroups called strata based on characteristics that they share

Question 3

advantage and disadvantage of stratified sampling

Answer 3

+ it is usually representative of the target population as p’s are in proportion to their occurrence and selected randomly
- it is very time consuming

Question 4

what is systematic sampling

Answer 4

a probability sampling method where researchers select members of the population at a regular interval. For example, every fourth person in a list could be used in the sample.

Question 5

advantage and disadvantage of systematic sampling

Answer 5

+ can be fairly unbiased as the researcher decides on system before seeing ps - so cant select particular person
- if participants selected by system dont want to take part then the system fails and it may make the sample unrepresentative

Question 6

what is random sampling

Answer 6

a sampling technique where every member of the target population has an equal chance of being selected.

Question 7

advantage and disadvantage of random sampling

Answer 7

+ usually representative and unbiased as every member of the target population has an equal chance of being selected
- can be difficult and time consuming to collect the list of all member of target population first

Question 8

what is opportunity sampling

Answer 8

the researcher selects anyone who is available and willing to take part in the study.

Question 9

advantage and disadvantage of opportunity sampling

Answer 9

+ it is quick and easy and requires no prior preparation because it uses those available at the time of testing
- it is likely to be biased as certain types of people will be unavailable and so may not apply to target population

Question 10

what is volunteer sampling

Answer 10

a sampling technique where participants self-select to become part of a study because they volunteer when asked, or respond to an advert.

Question 11

advantage and disadvantage of volunteer sampling

Answer 11

+ relatively easy as the only preparation needed is to place adverts and then participants contact them to take part
- likely to be biased and not apply to target population as only helpful people will apply