L6 - Sampling Techniques

Question 1

What is random sampling?

Answer 1

• This is when every member of the target population has the same chance of being selected
• e.g. place all names of the target population in a hat and draw names randomly to fit sample.

Question 2

Advantages of Random Sampling

Answer 2

The sample is likely to be representative and therefore results can be generalised to the target population.

Question 3

Disadvantages of Random Sampling

Answer 3

• Sometimes difficult to get full details of a target population from which to select a sample.
• Additionally, not all members of the target population who are selected to take part will be available or willing to take part, making the sample unrepresentative.

Question 4

What is systematic sampling?

Answer 4

This is a technique where participants are selected by taking every Nth person from a list.

Question 5

Advantages of systematic sampling

Answer 5

It is far simpler than random sampling

Question 6

Disadvantages of systematic sampling

Answer 6

• The process of selection can interact with a hidden periodic. trait within the target population.
• If the sampling technique coincides with the periodicity of the trait, the sampling technique will no longer be representative.

Question 7

What is stratified sampling?

Answer 7

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

Question 8

Advantages of stratified sampling

Answer 8

• All groups wishing a target population are included, therefore the sample should be representative of the target population.

Question 9

Disadvantages of stratified sampling

Answer 9

It can be very time consuming and the categories have to be identified and calculated.

Question 10

What is opportunity sampling?

Answer 10

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

Question 11

Advantages of opportunity sampling

Answer 11

This is the easiest and most practical of ensuring large samples

Question 12

Disadvantages of opportunity sampling

Answer 12

• There is a high chance that the sample will not be representative of the target population.
• Sometimes people may feel obliged to take part in research even when they do not really want too, this is unethical.

Question 13

What is volunteer sampling?

Answer 13

This involves people self selecting to participate in a study. The researcher will usually advertise for people to take part in their research.

Question 14

Advantages of volunteer sampling

Answer 14

This can be a useful way of finding specific people to take part in particular areas of research.

Question 15

Disadvantages of volunteer sampling

Answer 15

• A certain type of person (people more confident/helpful) tends to volunteer for research.
• This means that there is a high chance that the sample obtained will be unrepresentative (volunteer bias).