A Level Maths Sampling Methods Flashcards
1
Q
Random Sampling
A
Each thing in the sampling frame has an equal chance of being chosen, in order to avoid bias
2
Q
Systematic Sampling
A
Required elements are chosen at regular intervals in an ordered list
3
Q
Stratified Sampling
A
- Population divided into groups (strata)
- A simple random sample carried out in each group
4
Q
Quota Sampling
A
- Divide population into groups according to characteristic of interest
- Determine size of each group in sample to reflect proportions within the population
- Actively choose people with each group via suitable means
- Until the quota of each group is filled
5
Q
Opportunity Sampling
A
Find people at the same time the survey is being carried out
6
Q
Advantages of a Census (2)
A
- gives a completely accurate result
- no bias
7
Q
Disadvantages of a Census (4)
A
- time consuming
- expensive
- can’t be used when testing involves destruction
- large volume of data to process
8
Q
Advantages of a Sample (3)
A
- cheaper
- quicker
- less data to process
9
Q
Disadvantages of a Sample (2)
A
- data may not be accurate
- data may not be large enough to represent small sub groups
10
Q
Advantages of Simple Random Sampling (3)
A
- bias free
- easy and cheap to implement
- each unit has equal chance of being chosen
11
Q
Disadvantages of Simple Random Sampling (3)
A
- not suitable when population size is large
- may not be representative
- sampling frame needed
12
Q
Advantages of Systematic Sampling (3)
A
- simple and quick to use
- suitable for large samples/populations
- no bias
13
Q
Disadvantages of Systematic Sampling (2)
A
- sampling frame needed
- bias can be introduced if sampling frame not random
14
Q
Advantages of Stratified Sampling (1)
A
- guarantees proportional representation of groups within population
15
Q
Disadvantages of Stratified Sampling (3)
A
- population must be clearly classified into distinct strata
for selection within each strata: - may not be representative
- sampling frame needed
