In view of all these difficulties one has to resort to sampling
methods for collecting the data.
Sample is small proportion of
the population taken from the population to study the characteristics of
the population. By observing the sample one can make inferences about the
population from which it is taken.
Sampling is a technique adopted
to select a sample. The sample must represent or exactly duplicate the
characteristics of the population under study. In suchcase that sample is
called as a representative sample. The sampling method used for selecting a
sample is important in determining how closely the sample resembles the
population, in determining.
Sampling unit is the basic unit to
be sampled from the population which
cannot be further subdivided for the purpose of sampling. Head of the house is
the sampling unit for the household survey. In the study to know the average
age of a class, student is the sampling unit.
Sampling frame to adopt a sampling
procedure it is precisely about
necessary to prepare a list such that there exists, one to one that “one grain suffices correspondence
between sampling units and numbers. Such a list or map is called sampling
frame. A list of villages in a district, Student list of +1 and +2 students in
the above said example, A list of houses in a household survey etc.
Sample size is the number of units
in the sample.
The prime objective of the sampling is to get the representative
sample which will provides the desired information about the population with
maximum accuracy at a given cost.
Cost: Expenditure on conducting the survey is less compared to
Time: The consumption of time is relatively less in a sample
study than potentially generated voluminous data.
Accuracy: It is practically proved that the results based on
representative samples more reliable than the complete enumeration.
In the case of destructive type situations, sampling method is
the only way.
Accuracy depends on the honesty of the investigator
There is possibility for sampling error.