Research Methods - sampling

What is a target population?

• Everyone living in the country

• Everyone in a study

• A group of people who a researcher wants to study

• A group of people who take part in research

What is a sample?

• A group of people who take part in research

• A group of people who a researcher wants to study

• The methods used to select participants

• The extent to which findings can be generalised

What is a random sample?

• when every nth member of a target population is selected

• The sample reflects the proportions of people in subgroups with a population

• All members of the target population have an equal chance of being picked

• Selection is from people who are easily available

Select two weaknesses of a random sample

• Time consuming

• Can still be unrepresentative

• Volunteer bias

• Cheap

What is a systematic sample?

• Everyone has an equal chance of being picked

• every nth member of a population is chosen

• Anyone who is close by is selected

• Participants select themselves

Select one strength of a systematic sample

• Most popular method

• People volunteer themselves so they consent

• Easy to do

• No researcher bias

What is a stratified sample?

• People select themselves

• Find anyone who is around at the time

• The sample reflects the proportions of people in subgroups in a population

• Everyone in the target population has an equal chance of being picked

Select two strengths of a stratified sample

• Cheap and easy to carry out

• Representitive

• Generalisation is possible

• Participants volunteer so they consent

What is an opportunity sample?

• People who are easily available are selected

• People respond to an advert

• People in the population have an equal chance of being selected

• Every nth person in the target population is selected

Select two weaknesses of an opportunity sample

• Researcher bias

• Difficult to carry out

• unrepresentative

• Expensive