Sampling

What are the 5 main sampling methods?

Opportunity

Random

Stratified

Systematic

Volunteer

How would you get an opportunity sample?

Fidn the people most readily available (e.g. people walking down the street that you could ask to take part in your study)

How would you get a random sample?

Ensuring each member of the population has an equal chance of being chosen so participants could have their names drawn out of a hat or be randomly selected through a random number generator

How would you get a stratified sample?

Show calculations for how certain participants were obtained

How would you get a systematic sample?

Using the Nth person/thing on a list

How would you get a volunteer sample?

Advertise on a notice board or newspaper and ask potential participants if they would be interested in being part of a study

What are the strengths of an opportunity sample?

Easier and most convinient/quickest method

What are the strengths of a random sample?

Unbiased as everyone has an equal chance of being selected

What are the strengths of a stratified sample?

Involves precise information and everyone is represented

What are the strengths of a systematic sample?

Unbiased as it is random

What are the strengths of a volunteer sample?

Can access a variety of people which may make the sample more representative (so higher external validity)

What are the weaknesses of an opportunity sample?

There will inevitably be bias. Sample is taken from one part of the population

What are the weaknesses of a random sample?

A lot of time and effort can be put into it by gathering a list of all the participants, identifying a sample, contacting them. The samples are not always representative either and people may drop out.

What are the weaknesses of a stratified sample?

Cannot always reflect everyone’s views and it can be very time consuming to gather subgroups

What are the weaknesses of a sytematic sample?

It can sometimes take a while to put the lists together

What are the weaknesses of a volunteer sample?

Volunteer bias - keen participants may make more willing and helpful participants by nature