Module 1.0
Data Collection and
Conducting Surveys
©2017 Batangas State University
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Learning Objectives
• Demonstrate an understanding of the different
methods of obtaining data.
• Explain the procedures in planning and conducting
surveys and experiments.
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©2017 Batangas State University
Statistical Terms
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Statistical Terms
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Statistical Terms
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Statistical Terms
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Statistical Terms
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Statistical Terms
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Statistical Terms
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Statistical Terms
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Statistical Terms
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Statistical Terms
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Methods of Data Collection
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Collection of the data is the first step in conducting statistical inquiry.
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It simply refers to the data gathering, a systematic method of collecting and
measuring data from different sources of information in order to provide answers
to relevant questions.
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This involves acquiring information published literature, surveys through
questionnaires or interviews, experimentations, documents and records, tests or
examinations and other forms of data gathering instruments.
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The person who conducts the inquiry is an investigator, the one who helps in
collecting information is an enumerator and information is collected from a
respondent.
Methods of Data Collection
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In the field of engineering, the three basic methods of collecting data are through
retrospective study, observational study and through a designed experiment.
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A retrospective study would use the population or sample of the historical data
which had been archived over some period of time.
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In an observational study, process or population is observed and disturbed as little
as possible, and the quantities of interests are recorded.
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In a designed experiment, deliberate or purposeful changes in the controllable
variables of the system or process is done. The resulting system output data must
be observed, and an inference or decision about which variables are responsible
for the observed changes in output performance is made
Planning and Conducting Surveys
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A survey is a method of asking respondents some well-constructed questions. It is
an efficient way of collecting information and easy to administer wherein a wide
variety of information can be collected. The researcher can be focused and can
stick to the questions that interest him and are necessary in his statistical inquiry or
study.
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Surveys can be done through face-to-face interviews or self-administered through
the use of questionnaires.
Planning and Conducting Surveys
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When designing a survey, the following steps are useful:
1. Determine the objectives of your survey: What questions do you want to answer?
2. Identify the target population sample: Whom will you interview? Who will be the
respondents? What sampling method will you use?
3. Choose an interviewing method: face-to-face interview, phone interview,
selfadministered paper survey, or internet survey.
4. Decide what questions you will ask in what order, and how to phrase them.
5. Conduct the interview and collect the information.
6. Analyze the results by making graphs and drawing conclusions.
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Planning and Conducting Surveys
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In choosing the respondents, sampling techniques are necessary. Sampling is the
process of selecting units (e.g., people, organizations) from a population of
interest. Sample must be a representative of the target population. The target
population is the entire group a researcher is interested in; the group about which
the researcher wishes to draw conclusions.
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There are two ways of selecting a sample: the non-probability sampling and the
probability sampling.
Planning and Conducting Surveys
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Non-probability sampling is also called judgment or subjective sampling. This
method is convenient and economical but the inferences made based on the
findings are not so reliable. The most common types of non-probability sampling
are the convenience sampling, purposive sampling and quota sampling
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In convenience sampling, the researcher use a device in obtaining the information
from the respondents which favors the researcher but can cause bias to the
respondents. e.g. Online Poll, surveying your friend.
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In purposive sampling, the selection of respondents is predetermined according to
the characteristic of interest made by the researcher. e.g. interviewing group of ME
students regaring ME course
Planning and Conducting Surveys
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There are two types of quota sampling: proportional and non proportional.
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In proportional quota sampling the major characteristics of the population by
sampling a proportional amount of each is represented.
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For instance, if you know the population has 40% women and 60% men, and that
you want a total sample size of 100, you will continue sampling until you get those
percentages and then you will stop.
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Non-proportional quota sampling is a bit less restrictive. In this method, a
minimum number of sampled units in each category is specified and not concerned
with having numbers that match the proportions in the population.
Planning and Conducting Surveys
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In probability sampling, every member of the population is given an equal chance
to be selected as a part of the sample. There are several probability techniques.
Among these are simple random sampling, stratified sampling and cluster
sampling.
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Simple random sampling is the basic sampling technique where a group of
subjects (a sample) is selected for study from a larger group (a population). Each
individual is chosen entirely by chance and each member of the population has an
equal chance of being included in the sample.
Planning and Conducting Surveys
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A stratified sample is obtained by taking samples from each stratum or sub-group
of a population. When a sample is to be taken from a population with several
strata, the proportion of each stratum in the sample should be the same as in the
population.
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Cluster sampling is a sampling technique where the entire population is divided
into groups, or clusters, and a random sample of these clusters are selected. All
observations in the selected clusters are included in the sample