Chapter 1 Flashcards
Define convenience/opportunity sampling.
Choosing people who were readily available at the same time and place that the survey was carried out.
Give two advantages and two disadvantages of convenience/opportunity sampling.
Advantages:
- Very easy to carry out.
- Inexpensive.
Disadvantage:
- Unlikely to provide a representative sample.
- Highly dependent on the individual researcher.
Define quota sampling.
Dividing a population into characteristics of interest (strata) and finding the size of each strata in proportion to the population, then choosing people until the ‘quota’ (quantity) for each group is filled.
Give two advantages and two disadvantages of quota sampling.
Advantages:
- Allows a small sample to still be representative of the population.
- No sampling frame is required, so very quick and easy to carry out.
Disadvantages:
- Non-random sampling can introduce bias.
- Non-responses are not recorded.
Define simple random sampling.
Every item has an equal chance of being selected.
Give two advantages and two disadvantages of simple random sampling.
Advantages:
- Very easy and inexpensive to carry out.
- Removes bias.
Disadvantages:
- Not suitable for a large population.
- Requires a sampling frame.
Define stratified random sampling.
Dividing a population into characteristics of interest (strata) and a simple random sample carried out in each group.
Give two advantages and two disadvantages of stratified random sampling.
Advantages:
- Guaranteed to be proportionally representative of the groups within the population.
- Reflects population structure.
Disadvantages:
- Population must be clearly classified into distinct strata.
- Selection within each stratum has the same disadvantages as simple random sampling.
Define systematic random sampling.
Required elements are chosen at regular intervals in an ordered list.
Give two advantages and two disadvantages of systematic random sampling.
Advantages:
- Simple and quick to use.
- Suitable for large samples/populations.
Disadvantages:
- Sampling frame again needed.
- Can introduce bias if sampling frame is not random.
Define a census.
A survey taken on an entire population.
Give an advantage and a disadvantage of a census.
Advantage:
- Should give completely accurate result.
Disadvantage:
- Time consuming and expensive.
Define a sample.
A subset within the population intended to represent the entire population.
Give an advantage and a disadvantage of a sample.
Advantage:
- Cheaper and quicker.
Disadvantage:
- Data may not be as accurate.
