SAMPLING TECHNIQUES

Question 1

Opportunity Sample

Answer 1

Participants selected by using people who are most easily available
Easiest method, but it is biased as the sample is drawn from a small part of the target population.

Question 2

Volunteer Sample

Answer 2

Participants selected by asking for volunteers, by using advertisements.
Can collect a variety of participants, which is more representative, but it is biased because participants are likely to be motivated.

Question 3

Random Sample

Answer 3

Participants are selected using a random number technique.
Method is unbiased because members of the target population have an equal chance of selection, although at the end the researcher may end up with a biased sample as some people refuse to take part.

Question 4

Stratified and Quota Sample

Answer 4

Sub groups within a population are identified . Then a predetermined number of participants are taken from each subgroup in proportion to representations in the target population.
This is more representative as supplies a proportional representation of sub groups. But selection within sub groups may be biased due to opportunity sampling.

Question 5

Snowball Sampling

Answer 5

Start off with a few participants and then ask them to direct you to other participants.
Useful when participants are not easy to identify, e.g. those with eating disorders. But can biased because researchers may only contact people within a limited selection of the population.