sampling

Question 1

opportunity sampling

Answer 1

participants happen to be available at the time which the study is being carried out so are recruited conveniently

Question 2

opportunity strengths

Answer 2

easy method of recruitment which is time saving and less costly

Question 3

opportunity limitation

Answer 3

not representative - lacks generalisability

researcher bias - they control who they want to select

Question 4

random sampling

Answer 4

all members of population have same equal chances of being the one that is selected

Question 5

random strengths

Answer 5

no researcher bias
- researcher has no influence of who is picked

Question 6

random limitations

Answer 6

time consuming
- list of members of population and contacting them

volunteer bias
- participants can refuse so end up being unrepresentative sample

Question 7

systematic sampling

Answer 7

a predetermined system is used whereby every nth member is selected from the sampling frame
- numerical selection is applied consistently

Question 8

systematic strengths

Answer 8

avoids researcher bias and usually fairly representative of population

Question 9

systematic limitations

Answer 9

not truly unbiased
- unless using random number generator and then start the systematic sample which is then time consuming

Question 10

stratified sampling

Answer 10

the composition of the sample reflects the varying proportions of people in particular strata within the wider population

• first identify strat then calculate the required proportion needed for each stratum then select sample at random

Question 11

stratified strength

Answer 11

no researcher bias
- the selection within each stratum is done randomly

produces representative data due to the proportional strata hence generalisation is possible

Question 12

stratified limitation

Answer 12

time consuming to identify strata and contact people from each

complete representation of target population is not possible as the identified strata cannot reflect all the differences between the people in wider population

Question 13

volunteer sampling

Answer 13

involves self selection whereby the participant offers to take part either in response to an advert or when asked to

Question 14

volunteer strength

Answer 14

quick access to willing participants which makes it easy and not time consuming

as participants are willing to take part they are more likely to cooperate in the study

Question 15

volunteer limitation

Answer 15

volunteer bias - study may attract a particular profile of person - generalisability limited