3.2d Sampling

Question 1

Sampling definition

Answer 1

Gathering data from a group of respondents whose views or behaviour should be representative of the target market as a whole

Question 2

Advantages of sampling

Answer 2

• Understand customers want
• Predict outcomes of certain situations
• Quick and cheap

Question 3

Disadvantages of sampling

Answer 3

• Can be time consuming
• Can be costly
• Can be biased

Question 4

Confidence level definition

Answer 4

Degree to which statistics are a reliable predictor of actual events
E.g. 95% confidence level will be correct 19 out of 20 times

Question 5

What does random sampling ensure?

Answer 5

That every member of the public has an equal chance of being selected

Question 6

Advantages of random sampling

Answer 6

• Little risk of bias
• Simple
• Quick and cheap

Question 7

Disadvantages of random sampling

Answer 7

Assumes all members of the public are the same - unexpected bias

Question 8

How do you carry out stratified sampling?

Answer 8

Split the population into strata such as sex or age and take a sample from each one

Question 9

Advantages of stratified sampling

Answer 9

More reflective of population so results should be less biased

Question 10

Disadvantages of stratified sampling

Answer 10

• More costly/complex
• More time consuming
• May be hard to identify strata

Question 11

What is quota sampling?

Answer 11

Stratified sampling but selection is made by an interviewer who is given quotas to fill from sub-groups within the population
E.g. 50 females between the ages 18-30

Question 12

Advantages of quota sampling

Answer 12

• Quick

- Easy

Question 13

Disadvantages of quota sampling

Answer 13

Selection isn’t random

Question 14

What is ‘interviewer effects’?

Answer 14

When a response isn’t what the interviewee really thinks