Sampling Methods Flashcards
What is random sampling?
Every member of the target population has an equal chance of being selected for the sample.
For example, picking names out of a hat, or using a random number generator.
Give a strength of random sampling.
It is unlikely the sample will be biased, as the sampler has no control over who is in the sample.
All members of the target population have an equal chance of being chosen.
Give a weakness of random sampling.
Takes a long time, especially if there is a large target population.
Could be biased.
What is stratified sampling?
Gather a sample that is proportional of the target population.
Target population broken down into smaller groups, for example, gender or age.
You then sample from those groups.
Best method BUT least used.
Give a strength of stratified sampling.
Can be very representative of the population if done correctly. The whole population would be equally represented.
Give a weakness of stratified sampling.
Very time consuming and can be very difficult.
What is opportunity sampling?
The sampler selects ppts. from whoever is available at the time.
For example, whoever happens to be in your class when you want to gather data.
Give a strength of opportunity sampling.
It is convenient to do, as the sampler selects people who are there.
It is really easy and quick.
Likely to be ethical.
Give a weakness of opportunity sampling.
Tends to be less representative,because the sample was taken from a small section of the population.
Could be biased.
What is volunteer sampling?
Participants put themselves forward to be put into the sample.
For example, through a newspaper article (Milgram), TV advert, radio etc.
Give a strength of volunteer sampling.
Participants would be very motivated.
Quite easy to do.
Gives you access to a variety of people you would not normally have access to.
Give a weakness of volunteer sampling.
Volunteers are most likely to all be similar - tend to be more willing, and more eager to please than the wider population.
Could be biased.
