3.2d - Sampling Flashcards
Sampling definition
Gathering data from a group of respondents whose views should be representative of the target market as a whole
Advantages of sampling:
- Understand what customers want
- Predict outcomes
- Quick
- Cheap
Disadvantages of sampling:
- Can be time consuming
- Can be costly if the business want a more reliable result
- Can be biased
- Can be inaccurate
- Can become out of date quickly
Confidence level definition
The degree to which statistics are a reliable predictor of actual events
What does a 95% confidence level mean?
The prediction will be correct 95 out of 100 times
Interviewer effects definition
When a response isn’t what the interviewee really thinks
Advantages of random sampling:
- Little risk of bias
- Simple
- Cheap
- Quick
Disadvantages of random sampling:
Unexpected bias by assuming all members of population are the same
How is stratified sampling carried out?
The population is split into ‘strata’ (segments) and a random sample is taken from each one
Advantages of stratified sampling:
Less biased than random sampling as it is more reflective of the population
Disadvantages of stratified sampling:
- More costly and complex
- More time consuming
- May be hard to identify strata
- Not all members of strata are the same
How is quota sampling carried out?
Selection is made by the interviewer who is given quotas to fill from sub-groups within the population (e.g. 50 females between ages 18-30)
Advantages of quota sampling:
- Quick
- Easy
- More reflective of the whole population
Disadvantages of quota sampling:
- Selection isn’t random
- Assumes you know the structure of the whole population to build quotas from
