Sampling Techniques

Question 1

Random sampling

Answer 1

•every person in target pop has chance of being in sample randomise names
•no bias
•people could say no so it could be time consuming
•sample could be unrepresentative (all male)

Question 2

Opportunity sampling

Answer 2

•sample consists of people from target pop who are available just go and ask people to take part
•easier than random or stratified
•may not be representative of target pop
•could be researcher bias
•not everyone has chance of being selected people not in area can’t take part

Question 3

Systematic sampling

Answer 3

•predetermined system to select pps(he every fifth person is chosen)
•not affected by researcher bias
•sample may be unrepresentative of sample if every nth person has similar traits

Question 4

Volunteer sampling

Answer 4

•pps self select to take part in study by responding to ad or poster etc
•easier than random and stratified
•sample may not be representative

Question 5

Stratified sampling

Answer 5

•subgroups within a pop are identified and pps obtained from each stratum in proportion to target pop
•no affected by researcher bias and sample likely to be representative
•ensure subgroups in target pop are accurately identified is difficult and time consuming