L6: Sampling Techniques & Pilot Studies

Question 1

What is the target population?

Answer 1

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

Question 2

What is a sample?

Answer 2

It should be representative of the population from which it is drawn and should have the same characteristics as the population

Question 3

What is random sampling?

Answer 3

When each member of the target population has the same chance of being selected
E.g place all names of target population in a hat and randomly select

Question 4

Advantages and Disadvantages of Random Sampling

Answer 4

+ Large population = Large sample = more representative + generalised
+ No researcher bias as everyone has the same chance of being picked

• Difficult to get full details of a target population from which to select a sample as some people may not be registered
• Not everyone on the target population may be willing to take part

Question 5

What is Systematic Sampling?

Answer 5

Every Nth person is selected from a list. This becomes the sample

Question 6

Advantages and disadvantages of systematic sampling

Answer 6

+ Simpler than random sampling as it requires a list, but random sampling is time consuming

• Process of selection can have a hidden trait, and sample may no longer be representative
• Not all members who are chosen may be willing to take part

Question 7

What is opportunity sampling ?

Answer 7

Selecting participants that are available and willing.

Question 8

Advantages and Disadvantages of Opportunity sampling

Answer 8

+ Easiest and most practical method of getting large samples

• People may feel obliged to take part even if they don’t want to, this is unethical
• Will not be representative of the population

Question 9

What is Stratified sampling?

Answer 9

• Classifying population into categories and randomly choosing a sample with the same proportions in the population.

Question 10

Advantages and disadvantages of stratified sampling

Answer 10

+ All groups are included = representative

• Time consuming, and all details needed

Question 11

What is volunteer sampling?

Answer 11

People volunteering to participate in a study. Researchers advertise and people notice and decide whether to join the research

Question 12

Advantages and disadvantages of Volunteer sampling

Answer 12

+ Saves time and effort

• Certain type of person volunteers so unrepresentative sample