Sampling

What is ‘target population’?

• The group of people that the researcher wishes to study/the group the researcher wishes to apply their results to/ generalise to.

What is a sample?

• A (small) group of people taken from the target population and who are used by the researchers in their investigation.

What are different sampling methods?

• Random

• Opportunity

• Systematic

• Volunteer

• Stratified

How to complete random sampling?

•Get the sampling frame, which outlines the names of people in the target population

•Write the names on a piece of paper

•Put the names in the hat

•Randomly select the number of participants needed

•The sample is selected purely by chance

How to complete systematic protective?

1) Get the sampling frame, which outlines the names of people in the target population

2) Write the names on a piece of paper

3) Put the names in the hat

4) Randomly select the number of participants needed

5) The sample is selected purely by chance

How to complete stratified sampling?

1) Get the sampling frame, which outlines the names of people in the target population

2) Write the names on a piece of paper

3) Put the names in the hat

4) Randomly select the number of participants needed

5) The sample is selected purely by chance

Define volunteer sampling

• The volunteers select themselves (after seeing the study advertised).

• Usually paid

Define opportunity sampling

Selecting people who are most easily available at the time of the study.

	Strengths	Limitations
Random	There is no chance of researcher bias. This is because the method provides everyone an equal chance of selection. So the researcher cannot choose people who may give him the desired results.	This method does not guarantee a representative sample. This is because the participants may all consist of a certain subgroup. So findings cannot be generalised to the target population. If the is a large target population, random sampling may be time consuming for the researcher
Opportunity	This method is quick and easy.  As the researcher is choosing individuals who most readily available	This method may be open researcher bias. As the researcher gets to choose (consciously or unconsciously) participants who fit aim of researcher The sample may not be reflective of the wider population. This is if the sample all consist of a certain subgroup. So findings cannot be generalised to the target population.
Systematic	There is no chance of researcher bias. This is because the method provides everyone an equal chance of selection. So the researcher cannot choose people who may give him the desired results.	This method does not guarantee a representative sample. This is because the participants may all consist of a certain subgroup. So findings cannot be generalised to the target population. If the is a large target population, systematic sampling may be time consuming for the researcher
Stratified	Stratified sampling increases generalisation. As the sample is propionate to the target population Stratified sampling reduces research bias as the subsets of participants are selected randomly.	Stratified sampling is a difficult and time-consuming method for a researcher because they need to identify relevant subgroups in the target population and then calculate the proportion of each subgroup in the target population.
Volunteer	There is no researcher bias as the participants choose to take part in the study Quick and easy as the participants volunteer to take part	Volunteer sample may attract a certain ‘type’ of individual- making it unrepresentative.