Sampling Techniques

Question 1

What is the target population?

Answer 1

Everyone that a researcher would like to sample (who the results apply to)

Question 2

What is a sample?

Answer 2

Part of the population which are used to generalise results- should be representative of the population

Question 3

What are the advantages of sampling (as suppose to using the whole population)?

Answer 3

Cheap & Fast

Can perform without a sampling frame

Question 4

What are the advantages of using a whole population?

Answer 4

More accurate

Question 5

What are the different types of sampling techniques?

Answer 5

Random sampling
Systematic sampling
Stratified sampling
Opportunity sampling
Volunteer sampling

Question 6

How do you perform a simple random sample?

Answer 6

Give each item/participant a defining number and pick them from a hat or use a random number generator

Question 7

What are the pros and cons of simple random sampling?

Answer 7

+ No bias - each time has an equal chance of selection
+ Easy and cheap

• Could pick an unrepresentative sample by chance - not enough of one gender…
• Difficult & time consuming to get sampling frame and sample
• Not suitable for large number of participants

Question 8

What is systematic sampling?

Answer 8

Choosing the item/participant at regular intervals

Question 9

What are the pros and cons of systematic sampling?

Answer 9

+ Fastest way to get a sample
+ Suitable for large sample

• May have researcher bias - choose participants they want - may provide favourable results
• Unrepresentative sample - only access to certain part of the population

Question 10

What is stratified sampling?

Answer 10

Population divided in different groups (strata) and you randomly choose the proportional amount of people randomly from each group

Question 11

What are the pros and cons of stratified sampling?

Answer 11

+ Reflects population structure - representative
+ Avoids researcher bias - the don’t choose their participants

• Need sampling frame
• Researcher chooses the groups to be analysed - can be biased (researcher may determine some characteristics to me more important than other
• Too much time needed to make groups & sample them

Question 12

What is opportunity sampling?

Answer 12

Selecting participants who are readily available and willing to take part

Question 13

What are the pros and cons of opportunity sampling?

Answer 13

+ Most practical method of getting large samples
+ Fastest way to get a sample

• Can be biased or non- representative - researcher bias (choose pps they want)
• Not representative of whole population - only have access to a certain part of the population

Question 14

What is volunteer sampling?

Answer 14

When people are self selected to take part in a study - usually adverts

Question 15

What are the pros and cons of volunteer sampling?

Answer 15

Quick & easy method of getting participants
Suitable for a large sample

Volunteer bias - only certain type of person volunteers themselves (unemployed)
Unrepresentative sample - not accurately reflecting population structure