Sampling Flashcards
(9 cards)
1
Q
What is a single random sample?
A
Every sample of size n has an equal chance of being selected.
2
Q
What is a systematic sample?
A
The required elements are chosen at regular intervals from an ordered list.
3
Q
What is a stratified sample?
A
The population is divided into mutually exclusive strata, and a random sample is taken from each.
4
Q
What are the advantages of simple random sampling?
A
- Free of bias
- Easy and cheap to implement for mall populations and small samples
- Each sampling unit has a known and equal chance of selection
5
Q
What are the disadvantages of simple random sampling?
A
- Not suitable when the population size or the sample size is large as it is potentially time consuming, disruptive and expensive
- A sampling frame is needed
6
Q
What are the advantages of systematic sampling?
A
- Simple and quick to use
- Suitable for large samples and large populations
7
Q
What are the disadvantages of systematic sampling?
A
- A sampling frame is needed
- It can introduce bias if the sampling frame is not random
8
Q
What are the advantages of stratified sampling?
A
- Sample accurately reflects the population structure
- Guarantees proportional representation of groups within a population
9
Q
What are the disadvantages of stratified sampling?
A
- Population must clearly be classified into distinct strata
- Selection within each stratum suffers from the same disadvantages as simple random sampling
