Sampling methods can be broadly
classified into two types — probability and non-probability sampling.
In probability sampling the
probability of an element being included in the sample is known, though the
probability of inclusion may not be equal.
Probability sampling methods include
simple random sampling,
systematic sampling,
stratified sampling and
cluster sampling.
Non-probability sampling involves subjective judgment in
sample selection. It does not allow for the computation of sampling errors since the
probability of selection for each element in the population is unknown. Examples of
non-probability sampling methods include:
Examples of non-probability sampling include
quota sampling,
convenience sampling,
purposive sampling and
snowball sampling.
It is important to note that while non-probability sampling methods can be
practical and cost-effective, the lack of randomness in the selection process may limit the
generalizability of the findings to the broader population.
