Lecture note - Social research - Sampling

Sampling

Why we Why do we need to have sample?

To research entire population

- Too expensive to study

 - Too complicated

Terms

Representatives – if the aggregate characteristics of the sample closely approximate those same aggregate characteristics in the population

Population – aggregation of elements from which the sample is selected

Sample – selected element or respondent

Sampling bias – The over representation or under representation of some segment of the population in terms of a characteristic relevant to the research questions.

Probability sampling

- Involves random selection of elements in which each element has a chance of being selected.

- Primary method of selecting large, representative samples

- Provide useful descriptions of the total population

- Sample of individuals from a population containing essentially the same variations that exist in the population

e.g. Simple random sampling,  Systematic sampling, Stratified sampling, Cluster sampling, Stage sampling etc… 

Non-probability sampling

Involves non-random methods in the selection of elements in which not all have equal chances of being selected.

e.g. Snowball sampling, Quota Sampling etc…

Probability Sampling

Simple Random Sampling

- Selecting sample at random

- All samples have equal chance to be chosen   

e.g. using random numbers, toss a coin or dice… 

Systematic Sampling

- Every kth element in the total list is systematically chosen

Stratified Sampling

- Appropriate numbers of elements are drawn from homogeneous subsets of the population

- To avoid to include something not related to your research

Cluster Sampling

- cost effective sampling method
- divide the population into cluster and chose which clusters to measure 

Non-probability sampling

Convenient sampling
- Choosing the sample who are available at that time.

Judgmental Sampling Method/ Purposive Sampling Method

-The sample is based on the judgment of who the researcher thinks would be the best for the sample

Quota sampling

Judgment is used to select the subjects from each segment based on a specific proportion

e.g. gender, income levels, age, educational level

Snowball sampling

building up a sample through informants

First and foremost, Please read How Sociologist Do research.