Lesson 6: Sampling Techniques

Question 1

What are sampling techniques?

Answer 1

• involve samples drawn from a larger population
• used to obtain a sample of the target population and are essential to avoid studying entire target populations, which would take too long and be too expensive
• sample should be representative of the population it is drawn from so the findings of the study can be generalised to the target population

Question 2

Random sampling

Answer 2

• when every member of the target population has the same chance of being selected
• easiest way to do this is place all the names from the target population in a hat and draw out the sample required

Question 3

Random sampling evaluation

Answer 3

(+) is likely to be representative and therefore results can be generalised to the target population

(-) sometimes difficult to get full details of a target population from which to select a sample
(-) not all members of the target population who are selected to tale part will be available or willing to take part, making the sample unrepresentative

Question 4

Systematic sampling

Answer 4

A sampling technique where participants are selected by taking every nth person from a list

Question 5

Systematic sampling evaluation

Answer 5

(+) far simpler than simple random sampling

(-) the process of selection can interact with a hidden periodic trait within the target population, meaning the sampling technique will no longer be representative

Question 6

Stratified sampling

Answer 6

• involves classifying the target population into categories and then randomly choosing a sample that consists of participants from each category in the same proportions as they appear in the target population

Question 7

Stratified sampling evaluation

Answer 7

(+) all groups within a target population are included, therefore the sample should be representative of the target population

(-) can be very time consuming as all categories have to be identified and calculated, you would struggle to conduct a stratified sample without the details of all the people in your target population

Question 8

Opportunity sampling

Answer 8

• involves selecting participants who are readily available and willing to take part

Question 9

Opportunity sampling evaluation

Answer 9

(+) easiest and most practical method of ensuring large samples

(-) high chance that the sample will not be representative of the target population as sometimes people feel obliged to take part in research, even when they really do not want to, which is unethical

Question 10

Volunteer sampling

Answer 10

• involves people self selecting to participate in a study
• the researcher will usually advertise for people to take part in their research

Question 11

Volunteer sampling evaluation

Answer 11

(+) can be a useful way of finding specific people to take part in particular areas of research

(-) a certain type of person tends to volunteer for research and this means that there is a high chance the sample obtained will be unrepresentative (volunteer bias)