Page 66 - DMGT404 RESEARCH_METHODOLOGY

Research Methodology

Notes 3. Practicality: This implies that the sample design can be followed properly in the survey,
as envisaged earlier. It is necessary that complete, correct, practical, and clear instructions
should be given to the interviewer so that no mistakes are made in the selection of
sampling units and the final selection in the field is not different from the original sample
design. Practicality also refers to simplicity of the design, i.e. it should be capable of being
understood and followed in actual operation of the field work.
4. Economy: Finally, economy implies that the objectives of the survey should be achieved
with minimum cost and effort. Survey objectives are generally spelt out in terms of
precision, i.e. the inverse of the variance of survey estimates. For a given degree of precision,
the sample design should give the minimum cost. Alternatively, for a given per unit cost,
the sample design should achieve maximum precision (minimum variance).

It may be pointed out that these four criteria come into conflict with each other in most of the
cases,

!

Caution The researcher should carefully balance the conflicting criteria so that he is able to
select a really good sample design.

Self Assessment

Fill in the blanks:

5. A sampling plan should clearly specify the .................... population.
6. The sample size depends upon the .................... available with the company.

4.3 Types of Sample Design

Sampling is divided into two types:
Probability sampling: In a probability sample, every unit in the population has equal chances
for being selected as a sample unit.
Non-probability sampling: In the non-probability sampling, the units in the population have
unequal or negligible, almost no chances for being selected as a sample unit.

4.3.1 Probability Sampling Techniques

1. Random sampling.
2. Systematic random sampling.
3. Stratified random sampling.

4. Cluster sampling.
5. Multistage sampling.

Random Sampling

Simple random sample is a process in which every item of the population has an equal probability
of being chosen.

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