6 - Samplinng Techniques

Question 1

Define target population

Answer 1

The group who researchers are studying and want to generalise their results to

Question 2

Why don’t we study whole populations and take samples ins stead?

Answer 2

Too long

Too expensive

Question 3

Describe random sampling

Answer 3

Every member of the target population has the same chance of being selected e.g. put all names from population in hat and draw our sample

Question 4

Evaluate random sampling

Answer 4

+ sample is likely to be representative and therefore results can be generalised to target population

• difficult to get full details of a TP from which to select a sample
• not all members of TP who are selected will be available or willing to take part = unrepresentative

Question 5

Describe systematic sampling

Answer 5

Participants selected by taking every Nth person from a list

Question 6

Evaluate systematic sampling

Answer 6

+ simpler than random sampling

• process of selection can interact with a hidden periodic trait within TP. If sampling coincided with periodicity if trait, then not representative

Question 7

Describe stratified sampling

Answer 7

Involves classifying the postulation into categories and then randomly choosing a sample which consists of participants from each category in the same proportions as they are in the population.

Question 8

Evaluate stratified sampling

Answer 8

+ all groups within a population are included therefore representative

• time consuming as categories have to be identified and calculated
• if you don’t have details of all people in target population then you would struggle to conduct a stratified sample

Question 9

Describe opportunity sampling

Answer 9

Involves selecting participants who are available and willing to take part.

Question 10

Evaluate opportunity sampling

Answer 10

+ easiest and most practical method to ensure large sample

• high chance of being unrepresentative of TP
• people feel obliged to take part in research when they don’t want to = unethical

Question 11

Describe volunteer sampling

Answer 11

Involves people self - selecting to participate in a study. Researcher usually advertises for people to take part in research.

Question 12

Evaluate volunteer sampling

Answer 12

+ useful way to find people to take part in specific areas of research

• a certain type of person tends to volunteer = high chance that sample obtained is unrepresentative ( volunteer bias )