Basics of Research Methodology-Part-II

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Prepared by,
Dr.Pratibha A.Jagtap
Assistant Professor
Rajarambapu Institute of Technology,Rajaramnagar
Part-2
Sampling Design and Data Collection

2. Part-I-Sampling Design - Meaning of sampling,
characteristics of good sample design, steps in
sample Design, Types of sample design,
determining size of sample.
Part-II-Data collection-
Meaning, types of data, methods of collecting
primary data- observation, interview,
questionnaire and schedules, Secondary Data-
Sources of secondary data.
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5. Meaning of Sample, Sampling
Sample-A sample is a smaller representation of a large
whole.
Sampling-. Method of selecting a study portion of the
universe (total population) is known as sampling.
e.g.
When a patient has to undergo blood test the clinical
laboratory takes a few drops test it and them gives the
report.
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6.  Sample design is determined before data are collected.
 A sampling design is a definite plan for obtaining a
sample from a given population.
 It refers to the technique or the procedure the researcher
would adopt in selecting items for the sample.
 Sample design may as well lay down the number of
items to be included in the sample i.e., the size of the
sample.
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7. 1. Sample design should produce a representative sample
2. Sample design should produce a small sampling error
3. Sample design should be feasible within the research
study’s budgetary limits
4. Sample design should allow for the control of systematic
bias
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8. 1) Selecting the Population
2) Selecting the Sampling Frame
3) Specifying the Sampling Unit
4) Choosing the Sampling Method
5) Deciding the Sample Size
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9.  The target population is the group of people that the researcher
believes will provide the knowledge needed to complete the research
study.
 The researcher, while developing a sample design, must choose the
population according to his/her research study.
 Population can be finite or infinite.
 Population is finite if the number of elements in it are certain and
countable.
 In the case of infinite population, no figure can be given about the
number of elements in the population.
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10.  In research, Sampling Frame refers to a list or database of all the items or elements
or respondents in the population from which a sample can be chosen.
 Items or respondents can be selected from sampling frame to be included in the
given research project.
 It is sometimes preferable to choose a list of the population from which the
researcher selects units when selecting sample units from the population.
 The sampling frame is a collection of people or items
 E.g. a list of all playgroups in the researcher’s city
from which the researcher will select his or her sample.
 The sample is drawn from a list of all units in a study population. For example, in
order to perform his study, the researcher may include all playgroups in his
sampling frame located in his city.
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11. According to Organisation for Economic Cooperation and
Development (OECD), a sampling unit is one of the units
into which an aggregate is divided for the purpose of
sampling where each unit is regarded as individual and
indivisible when selection is made.
e.g. when a survey of a group of trees in a class is
conducted, a single tree is a sampling unit.
Each item or unit in the sampling frame is called as
sampling unit.

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12.  Choosing a sampling technique might take some time and entail a
number of options, such as whether to use classical sampling
approach, whether to sample with or without replacement, and
whether to employ non-probability or probability sampling.
 Whether a researcher uses probability sampling technique or non-
probability sampling technique usually depends on the purpose of
research.
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13. The number of units to be included in the
sample is the sample size.
Many factors influence the determination
of sample size including time, cost, and
facility.
Larger samples are better in general, but
they need more resources.
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15. While developing a sampling design, the researcher must pay
attention to the following points:
a. Type of universe
b. Sampling unit
c. Source ld
d. Size of sample
e. Indicators to study
f. Financial constraints
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16. While developing a sampling design, the researcher must pay attention to the following
points:
a. Type of universe:
 The first step in developing a sampling design is to clearly identify the universe to be
studied. The universe can be finite or infinite. In finite universe the number of items is
certain, for example number of workers in a factory, but in case of an infinite universe
we do not know the total number of items, for example listeners of a radio
programme.
b. Sampling unit:
 A decision has to be taken concerning a sampling unit before selecting sample.
Sampling unit may be a geographical one such as state, district, village, etc., or a
social unit such as family, individual, school, etc. The researcher will have to decide
one or more of such units that he has to select for this study.
c. Source list:
 It is also known as sampling frame from which sample is to be drawn. It contains the
names of all items of a universe. If source list is not available, researcher has to
prepare it. The list should be comprehensive, reliable and appropriate. It is important
to be as representative of the population as possible.
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17. d. Size of sample:
 This refers to the number of items to be selected from the universe to constitute a sample.
Choosing the number is a major challenge before a researcher. The size of sample should
neither be large, nor too small. The number should be optimum. While deciding the size of
sample, researchers must determine the desired precision as also an acceptable confidence
level for the estimate. The indicators of interest in a research study must be kept in view,
while deciding the size of the sample. Also, the costs factor also kept in mind while choosing
the size of sample.
e. Indicators to study:
 In determining the sample design, one must consider the question of the specific population
parameters which are of interest. For instance, you may be interested in estimating the
proportion of persons with some characteristic in the population, or you may be interested in
knowing some average or the other measure concerning the population. There may also be
important sub-groups in the population about whom you would like to make estimates.
f. Financial constraints:
 Cost considerations, from practical point of view, have a major impact upon decisions relating
to not only the size of the sample but also to the type of sample.
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18. Sampling method can be broadly classified as
I)Random or probability sampling
II) Non-random or non-probability sampling.
I)Random or probability sampling
 Under Random or Probability Sampling, every element of the population enjoys
equal chance of being selected.
 E.g. suppose from 2,000 students in a college, 200 are selected at random then
every one of these 2,000 students has equal chance of getting selected .
II) Non-random or non-probability sampling.
 Under Non-Random or Non-Probability Sampling , elements will have constituting
the sample are selected on some basis.
 e.g.200 students out of 2000 may be selected on such a way that there are 50 pure
science students. In this case the sample is purposively selected. So it is not
random sample.
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20. Sampling method can be broadly classified as
I)Random or probability sampling
A)Simple or Non-Restricted Probability Sampling
B)Restricted probability Sampling
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21. Sr.No. Simple (or) unrestricted
sampling
Restricted Sampling
1 Lottery Method Stratified
2 Table of Random Number Systematic
3 Multistage
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22. I. Simple (or) unrestricted sampling
1.Lottery Method:
In this method all the terms in the population are given numbers and
These are written on chits of uniform size. Then these chits are
placed in a local or a bag and the required number of chits are
selected.
2.Table of Random number:
 In this method, first the size of the sample is determined. Then using
random number table, the required number of items is selected to
form the sample.
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23. Stratum means a layer/group, Population from which samples are to be
selected may contain a number of group/layers. From each layer/group, a
few samples are selected.
e.g.
Suppose for a research work on the literacy level in Rajasthan, data is collected from all places in
Rajasthan. Adopting stratified random sampling, first the state is divided on to different districts, A few
districts are selected at random. Then those districts are divided into Panchayat Unions.
From this second stratum a few Panchayat unions are selected.
Each Panchayat union divided into Panchayats and a few panchayats are selected at random. Then
each panchayats containing a number of villages, a few villages are selected at random.
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24.  In this method the sample is formed by selecting the first unit at random and them
selecting the remaining items at evenly spaced intervals.
 For example suppose from 2000 college students we have to select a sample of 50
students. First we determine the sampling interval (k). this is obtained by dividing
the size of population by sample size (i.e.40; 2000/50) = 40.Them from serial
number 0001 to 0040 we selected at random a serial number. Suppose we have
selected with the serial number 15 with that we add 50 for another Sample, so the
sample will be as 15, 65, 115,… and soon.
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25. As the name suggests, in this method, the
samples are selected at different stages
here the population is first divided into
different stages. All the samples at random
at different stages will possess the common
characteristics or will be homogeneous on
some basis.
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27. Sr. No. Methods
1 Judgment
2 Convenience
3 Quota
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28. Non random sampling or Non-probability
Sampling refers to the sampling process in which
the samples are selected for a specific purpose
with pre-determined basis of selection.
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29.  In this method, the sample selecting is purely based on the judgment of the
researcher.
 This is because the researcher may lack information regarding the population from
which he has to collect the sample.
 Population characteristics not known in such cases the researcher can use this
method.
 Once the sample size is determined the investigator is free to select any item on the
field.
 For example, suppose 100 boys are to be selected from a college with 1000 boys if
nothing is known about the students in this college, then the investigator may visit the
college and choose the first 100 boys he met or he may select 100 boys all belonging
to III year or he might select 50 boys from commerce and 50 from science.
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30. This method of sampling involves selecting the
sample elements using some convenient method
without going through the rig our of sampling
method.‟
e.g., suppose 100 car owners are to be selected.
Then we may collect from the RTO‟s office the list
of car owners and then make a selection of 100
from that the form the sample.
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31. In this method, the sample size is determined first and then quota is
fixed for various categories of population, which is followed while
selecting the sample,
E.g. Suppose we want to select 100 students, and it might say that
selection of sample be according to the quota given below.
Boys 50% and girls 50%
 Then for 50%, among the boys, 50% students from FY class and
50% from SY class will be selected and same or different for girls
will be used.
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32.  Generally, a sample must be of an optimum size i.e., it should not be
too large nor too small.
 Normally the size should be large enough to give a confidence
interval of desired width and as such the size of the sample must be
chosen by some logical process.
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33.  Nature of universe
 Number of groups
 Nature of study
 Sample Technique
 Accuracy and confidence level
 Resources available
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34. 1.Nature of universe
 When the items of the universe are homogenous, a small sample can serve the purpose, suppose
they are heterogeneous, a large sample would be required.
2.Number of groups:
 When a researcher forms class – groups a large sample is necessary as a small sample might not
be able to give a reasonable number of items in each class-group.
3.Nature of study:
 When the researcher examines the items very intensively and continuously then the sample should
be small. He may prefer general survey when the size of the sample is large but a small sample is
considered appropriate in technical surveys.
4.Sample Technique:
 The researcher has to decide the sampling tools while determining the size of the sample A small
random sample is better than a larger but badly selected sample.
5.Accuracy and confidence level:
 A researcher requires a large size sample when the accuracy or the level of precision is to be kept
high. To get more accuracy for a fixed significance level the samples size has to be increased
fourfold.
6.Resources available:
 What amount of time and financial resources are available to the researcher will determine the size
of sample, with sufficient time and large volume of funds available the sample size could be large
otherwise it should be small.

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36. Meaning, Types of data, methods of collecting
primary data- observation, interview,
questionnaire and schedules, Secondary Data-
Sources of secondary data.
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37.  Data refers to information of facts often researchers
understand by data only numerical figure.
 It also includes facts non-numerical information
qualitative and quantitative information in a research of
the data are available the research is half-complete.
 Data could be broadly classified as primary data and
secondary data they are also mentioned as sources of
data.
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38. PRIMARY SOURCES
SECONDARY SOURCES
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39.  1. OBSERVATION
 2.INTERVIEW
 3.QUESTIONNAIRE
 4.SCHEDULE
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40. PRIMARY (DATA) SOURCES
1. OBSERVATION;
 Observation as a method of data collection is used very frequently whenever
collection of data through other methods is difficult for example it is not always
possible to conduct interviews with every person to collect required information.
 For instance, suppose a scholar wants to study the life style of hill tribe. It is
certainly not possible to use a questionnaire or schedule or interview only
alternative available is observation as the respondents would not rely any
question orally or in written.
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41.  Interview method involves direct or indirect meeting of the
respondents by the researcher.
 The researcher determines the questions to be raised at the time of
interview and elicit the response for them.
 The reply given is either written down in a note book or recorded in
audio or video cassette.
 This method has to be necessarily adopted whenever details
regarding any confidential matter are to be collected or the research
requires data collection directly from the respondents.
Interview may be broadly classified as
 1.Direct interview
 2.Indirect interview
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42.  A questionnaire is a sheet(s) of paper containing questions relating
to certain specific aspect. Regarding which the researcher collects
the data. The questionnaire is given to the important or
 respondent to be filled up.
 Sometimes questionnaire is also in the form of files generated
through computer.
 This usually called soft copy of questionnaire.
 Generally to test the reliability of the questionnaire, it should be
tested on a limited scale and this is technically known as Pilot
Survey.
 The objective of a pilot survey is to filter unnecessary questions, and
the questions which are difficult to answer.
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43. Open ended
Close ended
Pictorial
Dichotomous Multiple choice
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44. In these questions the respondents are
given freedom to express their views as
there is wide range of choice. E.g.
“How would you describe the use of this
soap”?
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45. These type of questions do not allow the
respondents to given answers freely E.g.
“Would you describe the smell of this soap
is attractive”?
Yes / No
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46. In this type of questions, picture are drawn,
and the respondents indicate the answer
by selecting the pictures he prefers.
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47. In this questions two alternatives are given
a positive one and a negative one. E.g.
“Do you own a watch”? Yes No
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48.  Schedules (contains a set of questions) are being filled in
by the enumerators who are specially appointed for the
purpose.
 Enumerators go to respondents, ask them questions
from the proforma in the same order in which the
questions are listed and record the replies on the space
given.
 Enumerators should be trained Example: Population
census.
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49.  The secondary data, are those which have already been
collected some other agency and which have already
been processed.
 Generally speaking secondary data is collected by some
organization to satisfy its own need but it is being used
by various departments for different reasons. For
example, census figures taken are used by social
scientists (economists) for social planning and research.
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50.  Internal Sources: Registers, Documents, Annual Reports, Sales Reports,
previous Research papers , Sales records, invoices etc.,
 External Sources: Journals on magazines, newspapers, public speeches,
state and central govt., departments, reports etc.,
 The information had from any published documents which may documents
the researcher should consider the following points:
 Exactly what products are included in the statistical classification
 Who originally collected the data for what purpose, and whether three might
any
 motive for misrepresentation‟
 From whom the data were collected and how reliable the methodology might
have been and
 How consistent the data are with other local or international statistics.
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