2. 2
14MBA23 – Research Methods
Syllabus:
Sampling: Concepts- Types of Sampling -
Probability Sampling – simple random
sampling, systematic sampling, stratified
random sampling, cluster sampling -Non
Probability Sampling – convenience sampling-
judgemental sampling, snowball sampling-
quota sampling – Errors in sampling.
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14MBA23 – Research Methods
SAMPLING:
For a researcher, he needs to gather information
for his study and he selects a part of the
population for his study, which resembles by
Characteristics, which the researcher wants to
be studied.
In simple language, Sample is a unit of the large
quantity, it may be products or a part of a
population required for the study.
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14MBA23 – Research Methods
SAMPLING: CONCEPTS OF SAMPLING:
There may be a number of Concepts in Sampling which can
include,
i) Population (all units in a region),
ii) Sampling Unit (Identifyable units in the population),
iii) Sampling Design (Samples selected based on their possible
probabilities),
iv) Sampling frame (The design can be the specific population
like Indian Villages or Illiterates and so on),
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14MBA23 – Research Methods
SAMPLING: CONCEPTS OF SAMPLING:
v) Random Sample: (Explanation is not required),
vi) Non-Random Simple: (Explanation not required)
vii) Population Parameters: (What basis population can be
calculated – Its the mean or its average and variance of the
population)
viii) Statistic, Estimator and Estimate: (It need to be calculative,
statistical information/ data to be gathered)
ix) Sample Design: (Sample design will specify every possible
probability of being drawn)
x) Sampling errors: (Sample error is difference between the
statistic used to estimate and the actual but unknown values of
the parameters)
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14MBA23 – Research Methods
SAMPLING: CONCEPTS OF SAMPLING:
What is mean, median and mode?
Mean – The average., Ex: 3, 4, 6, 1, 3, Add all and divide it gives
the mean. (Total/ No of units = Mean – 17/5 = 3.4 is the mean)
Median – The center number in the arranged series, Ex:
3,4,6,1,3 shall be arranged into one 1,3,3,4,6, here in the five
numbers, the middle number is 3 Hence 3 is the median,
Mode – The common number in the series, Ex: 3,4,6,1,3 the
common number appearing the hightest time is 3 hence Mode
is 3.
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14MBA23 – Research Methods
SAMPLING:
Purpose/ Features of Sampling:
i) Lowering the cost (Economical),
ii) Greater accuracy of results (Reliable, Accuracy,
Stability, Scientific – Probability or Non-Probability),
iii) Speedy in data collection (Less Time Consuming),
iv) Availability of population for test,
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14MBA23 – Research Methods
STEPS IN DEVELOPING SAMPLING PLAN:
i) Define the target population, (Characteristics)
ii) Select the data collection method, (Interview, Observation)
iii) Identify sampling frames needed, (Eligible Sampling Units)
iv) Select appropriate sampling method,(Probability or Non
Probability Method)
v) Determine necessary sample sizes and overall contact
rates, (Sample size, Time and Money Reqd)
vi) Creating an operating plan for selecting sampling units,
(How to reach the respondents)
vii) Execution of the operational plan.(Start with consistency and
control)
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14MBA23 – Research Methods
Determination of Appropriate Sampling Design:
i) What's the research objective,
ii) What is the scope of the research,
iii) What are the availability of resources (Primary resources/
secondary resources),
iv) What is the time required to perform the sampling,
The next is (After the collection of the sample data)
v) Is the target population knowledge adequate,
vi) Is the appropriate tools used for the sampling,
vii) Is the solution accurate.
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14MBA23 – Research Methods
Factors influencing the sample size are:
i) Size of the population,
ii) Availability of the resources (Primary or secondary),
iii) Degree of accuracy desired,
iv) Homogeneity (Same) or Hetrogenity (Different) of the
population,
v) Nature of Study,
vi) Method of sampling adopted,
vii) Nature of respondents
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14MBA23 – Research Methods
Merits and Demerits of sampling:
Merits of Sampling:
i) Sampling saves/ consumes less time,
ii) Sampling provides more information,
iii) Sampling provides information at less cost,
iv) Sampling is scientific,
v) Sampling results are reliable.
Demerits of Sampling: If proper place, time, respondents,
techniques or tools, are selected wrong it has lots of
demerits, like Inaccuracy, Misleading, or leads to
complications and confusions.
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14MBA23 – Research Methods
Errors in Sampling: Errors can be in two types: (a)
Biased and (b) Unbiased Errors
(a) Biased Errors are those errors due to bias of prejudice
(unreasonable) on the part of the respondent or informant,
or/ and on the part of the researcher in selection of
respondent, or method of data collection.
(b) Unbiased Errors are those errors which is occured
accidental without the knowledge of the researcher,
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling or Techniques in
Sampling:
i) Probability Sampling,
ii) Non-Probability Sampling.
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling
i) Probability Sampling (Non-Zero Probability),:
a) Simple Random Sampling,
b) Systematic Random Sampling,
c) Stratified Random Sampling,
d) Cluster Sampling,
e) Multi-Phase Sampling or Sequential Sampling,
f) Sampling with probability proposition to size.
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling
ii) Non-Probability Sampling,:
a) Convenience Sampling,
b) Judgment Sampling,
c) Quota Sampling,
d) Snowball Sampling,
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling - Probability Sampling,:
a) Simple Random Sampling:
Simple Random Sampling refer to the sampling technique
where the respondents are gathered randomly. In random
sampling this is done as,
i) Every respondent is equally qualified for the selection
chosen for the sample,
ii) Every respondent has the equal probability, in
determining the results.
Example: Out of 56 students, 10 were taken randomly.
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling - Probability Sampling,:
b) Systematic Random Sampling: Systematic Random
Sampling is the sampling, where out of the target
populatio, sample is collected in a systematic manner.
Example: In the class attendance list, every fifth student
shall be taken for sampling,
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling - Probability Sampling,:
c) Stratified Random Sampling: Stratified Random
Sampling, refers when the population is divided into
certain classes or social layers to form a individual
sample.
Example: Sampling stratefied on the basis of caste or
religion or education or life style.
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling - Probability Sampling,:
d) Cluster Sampling: Cluster sampling is a probability
sampling method in which the sampling units are divided
into mutually exclusive and collectively exhaustive
subpopulation called Clusters.
Cluster sampling is 'Single Stage (One Stage)' and 'Multi
Stage (Several Stage)' Cluster Sampling, and if
distributed geographically then it is 'Area Sampling'.
Cluster sampling may or may not have approximate
number of elements/ subjects in each cluster.
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling - Probability Sampling,:
e) Multi-Phase Sampling: Multi-phase Sampling is also
called as Sequential Sampling and Double Sampling as
the first sample is taken for preliminary study and further
thereon it is taken for more details and further
informations.
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling - Probability Sampling,:
f) Sampling with probability propositional to size:
This refers that the sampling where each sample is selected
ramdomly or systematically or stratified, (as per the
selection of the researcher), but each sample shall have
the same size, for samples tends to have a uniform study.
This sampling is less expensive and the process is more or
less, like the simple random sampling.
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14MBA23 – Research Methods
SAMPLING:
Types of Sampling
ii) Non-Probability Sampling,:
a) Convenience Sampling,
b) Judgment Sampling,
c) Quota Sampling,
d) Snowball Sampling,
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14MBA23 – Research Methods
Types of Sampling
ii) Non – Probability Sampling:
a) Convenience Sampling:
i) Convenience Sampling is a Non-Probability Sampling.
ii) Convenience Sampling is the sampling where the researcher has the
freedom to choose sampling of his choice or convenient.
Iii) Convenience Sampling is usually performed during the
Exploratory Research Phase of a research project.
iv) Convenience Sampling is the method where the researcher is able to
collect informations quickly and efficienctly.
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14MBA23 – Research Methods
Types of Sampling
ii) Non – Probability Sampling:
b) Judgment Sampling: i) Judgment Sampling is a non-
probability Sampling,
ii) Judgment Sampling is used in exploratory research
process,
iii) Judgment Sampling is selected on researcher's beliefs to
meet the research,
iv) Judgment Sampling is performed to collect information
which is advantageous to the researcher.
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14MBA23 – Research Methods
Types of Sampling
ii) Non – Probability Sampling:
c) Quota Sampling: i) Quota Sampling is a Non-Probability
Sampling,
ii) Quota Sampling is selection on pre-specified quotas,
iii) Quota Sampling is selection based on Age, Sex, Occupation,
Income or Rural or Urban and so on.
iv) Quota Sampling can be based on demographic specifications,
like Nanjangud Area, Siddartha Lay out, MBA Students.,
v) Quota Sampling is done to ensure that the group/ quota
selected is able to adequately represent the study.
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14MBA23 – Research Methods
Types of Sampling
ii) Non – Probability Sampling:
d) Snowball Sampling: i) Snowball Sampling is another
non-probability Sampling,
ii) Snowball Sampling is also called as 'Referral Sampling'.
iii) Snowball Sampling makes the respondent to refer another
potential respondent,
iv) Snowball Sampling is usually done where the
respondents are small in number and unique to fulfill the
requirement in the research.