Types of Sampling

Question 1

Simple random sampling

Answer 1

Definition: Every member of the population has an equal chance of being selected. (Uses sampling frame - Think random number generator)

Strengths: High representativeness; minimizes bias.

Weaknesses: Requires a complete list of the population; not always practical.

Question 2

Systematic sampling

Answer 2

Definition: Selection of every nth individual from a list or sequence. (uses sampling frame)

Strengths: Simpler than random sampling; ensures coverage across the population.

Weaknesses: Risk of periodicity bias; requires a list.

Question 3

Stratified sampling

Answer 3

Definition: Population divided into subgroups (strata) that are meaningful to the research question; random samples taken from each stratum.

Strengths: Enhances representativeness of significant subgroups.

Weaknesses: Requires detailed population information; more complex to organise.

Question 4

Cluster sampling

Answer 4

Definition: Population divided into clusters; a random sample of clusters is selected, and all or a random sample of members from chosen clusters are surveyed. (Needs sampling frame)

Strengths: Cost-effective for large, geographically dispersed populations.

Weaknesses: More variance than simple random sampling; clusters may not be homogeneous.

Question 5

Convenience sampling

Answer 5

Definition: Sampling based on availability and willingness to participate. (No sampling frame needed)

Strengths: Easy and inexpensive.

Weaknesses: High risk of bias; not representative.

Question 6

Snowball sampling

Answer 6

Definition: Participants recruit other participants among their acquaintances.

Strengths: Useful for reaching hidden or hard-to-reach populations.

Weaknesses: Potential for high bias; not representative.

Question 7

Purposive sampling

Answer 7

Definition: Selection based on specific characteristics or qualities; researcher’s judgement.

Strengths: Targets relevant participants for qualitative research.

Weaknesses: Subjective; potential for bias.

Question 8

Quota sampling

Answer 8

Definition: Ensures representation of specific characteristics in the sample to match their proportions in the population.

Strengths: More controlled than convenience sampling; ensures diversity.

Weaknesses: Non-random; potential for selection bias.

Question 9

Factors to consider

Answer 9

Research goals, population size and diversity, resource availability, and time constraints.

And of course, PERVERT