Stats chapter 1 (non-random sampling) Flashcards
What are the two types of non-random sampling?
- Quota sampling
2.Opportunity/convenience sampling
When is quota sampling used usually?
When the sampling frame is unknown (e.g. all the right and left handed people in the UK)
What is a quota?
a fixed share/number of something
What is quota sampling?
Population is divided into groups according to characteristic. A quota of items/people in each group is set to try and reflects the groups proportion in the whole population
How is quota sampling carried out?
An interviewer selects the actual sampling units
What are the advantages of quota sampling? (3)
- no sampling frame required
- quick, easy and inexpensive
- allows a small sample to still be representative of the population
What are the disadvantages of quota sampling? (2)
- non-random sampling can introduce bias
- population must be divided into groups, which can be costly or inaccurate
What is a variant of quota sampling called?
opportunity/convenience sampling
What is opportunity/convenience sampling?
A sample taken from people who are available at the time of study, who meet the criteria
How is opportunity/convenience sampling carried out?
the interviewer selects the actual sampling units according to the set criteria
State the advantages of opportunity/convenience sampling? (2)
- easy to carry out
- inexpensive
What are the disadvantages of opportunity/convenience sampling? (2)
- unlikely to provide a representative sample
- highly dependent on individual researcher
What are the 2 types of data?
- qualitative/categorical
- quantitative
What is Qualitative/categorical data?
non-numerical values, e.g. colour
What is quantitative data?
numerical values
