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Sampling Techniques

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Sampling Techniques

Probability Sampling: this Sampling technique uses


randomization to make sure that every element of the population
gets an equal chance to be part of the selected sample. It’s
alternatively known as random sampling.
Non-Probability Sampling: it does not rely on randomization.
This technique is more reliant on the researcher’s ability to select
elements for a sample. This type of sampling is also known as
non-random sampling.
Types of Probability Sampling
• Simple random sample
• Systematic sample
• Stratified random sample
• Cluster sample
Simple Random Sampling
Every element has an equal chance of getting
selected to be the part sample. It is used when
we don’t have any kind of prior information
about the target population.

For example: Random selection of 20 students


from class of 50 student. Each student has
equal chance of getting selected. Here
probability of selection is 1/50.
Systematic Random Sampling
Here the selection of elements is systematic and not random except
the first element. Elements of a sample are chosen at regular intervals
of population. All the elements are put together in a sequence first
where each element has the equal chance of being selected.
Stratified Random Sampling
This technique divides the elements of
the population into small subgroups
(strata) based on the similarity in such
a way that the elements within the
group are homogeneous and
heterogeneous among the other
subgroups formed. And then the
elements are randomly selected from
each of these strata. We need to have
prior information about the population
to create subgroups.
Cluster Random Sampling
Our entire population is divided into
clusters or sections and then the
clusters are randomly selected. All the
elements of the cluster are used for
sampling. Clusters are identified using
details such as age, gender, location etc.
Types of Non-Probability Sampling
• Convenience Sampling
• Purposive Sampling
• Snowball Sampling
• Quota Samplings
Convenience Sampling
Here the samples are selected based on the availability.
This method is used when the availability of sample is rare
and also costly. So based on the convenience samples are
selected.
For example: Researchers prefer this during the initial
stages of survey research, as it’s quick and easy to deliver
results.
Purposive Sampling
This is based on the intention or the purpose of study. Only
those elements will be selected from the population which
suits the best for the purpose of our study.
For Example: If we want to understand the thought
process of the people who are interested in pursuing
master’s degree then the selection criteria would be “Are
you interested for Masters in..?”
Snowball Sampling
This technique is used in the situations where
the population is completely unknown and rare.
Therefore we will take the help from the first
element which we select for the population and
ask him to recommend other elements who will
fit the description of the sample needed.
Quota Sampling
This type of sampling depends of some pre-set standard. It
selects the representative sample from the population.

For example: If our population has 45% females and 55%


males then our sample should reflect the same percentage
of males and females.

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