Types Of Sampling Design

Question 1

Probability?

Answer 1

• simple random.
• systematic random.
• stratified random.
• cluster.
• multi-stage.

Question 2

Non-probability?

Answer 2

• convenience.
• snowball.
• quota.
• purposive.

Question 3

Simple random sampling.

Answer 3

• equal chance of selection.
• several methods e.g. Using a statistical software package or random number tables.
• advantages:
• easiest method and most commonly used.
• high generalisability of findings.
• disadvantages:
• not as efficient as stratified random sampling.

Question 4

Systematic random sampling.

Answer 4

• systematically selected from a list at intervals that are predetermined by the researcher.
• advantages:
• very easy to use and implement.
• disadvantages:
• systematic biases are possible.

Question 5

Stratified random sampling.

Answer 5

• population is divided into groups known as ‘strata’ by implementing SRS.
• advantages:
• cost-effective.
• disadvantage:
• less efficient as you need a larger sample.

Question 6

Multistage random sampling.

Answer 6

• carried out in various stages.
• advantage:
• when the others are too complex and expensive to conduct.

Question 7

Convenience sampling.

Answer 7

• when participants are chosen because they are ‘convenient’ e.g. They are in close proximity to the researcher.
• advantages:
• easy access to participants.
• cost effective.
• can provide rich qualitative data.
• disadvantages:
• does not produce representive samples.
• results are hard to replicate.

Question 8

Snowball sampling.

Answer 8

• identify someone who meets the criteria for your study, who leads you to your next participant.
• advantages:
• used for hard-to-reach participants that would typically be hard to access.
• cost-effective.
• disadvantages:
• not used for generalisations.
• relies on the participants themselves to increases the sample size.

Question 9

Purposive sampling (or judgemental/selective/subjective).

Answer 9

• looks for cases that are rich or in-depth in information.
• advantages:
• can provide the researcher with justifications to make generalisations.
• disadvantages:
• a high probability of research bias.

Question 10

Quota sampling.

Answer 10

• chosen according to pre-specified quotas regarding demographics, attitudes, behaviours, or some other criteria.
• advantages:
• ensured selection of adequate numbers of subjects with appropriate characteristics for the study.
• disadvantages:
• not used for generalisations.