Page 10 - DMGT209_QUANTITATIVE_TECHNIQUES_II

Unit 1: Quantitative Techniques for Managers

1.3.1 Types of Statistical Data Notes

An effective managerial decision concerning a problem on hand depends on the availability and
reliability of statistical data. Statistical data can be broadly grouped into two categories:

 Secondary (or published) data
 Primary (or unpublished) data
The secondary data are those which have already been collected by another organisation and are
available in the published form. You must first check whether any such data is available on the
subject matter of interest and make use of it, since it will save considerable time and money. But
the data must be scrutinized properly since it was originally collected perhaps for another
purpose. The data must also be checked for reliability, relevance and accuracy.
A great deal of data is regularly collected and disseminated by international bodies such as:
World Bank, Asian Development Bank, International Labour Organisation, Secretariat of United
Nations, etc., Government and its many agencies: Reserve Bank of India, Census Commission,
Ministries-Ministry of Economic Affairs, Commerce Ministry; Private Research Organizations,
Trade Associations, etc.
When secondary data is not available or it is not reliable, you would need to collect original data
to suit your objectives. Original data collected specifically for a current research are known as
primary data. Primary data can be collected from customers, retailers, distributors, manufacturers
or other information sources. Primary data may be collected through any of the three methods:
observation, survey, and experimentation.

Data are also classified as micro and macro. Micro data relate to a particular unit or region
whereas macro data relate to the entire industry, region or economy.

Operations Research

You would recall that in Operations Research a mathematical model to represent the situation
under study is constructed. This helps in two ways. Either to predict the performance of the
system under certain controls or to determine the action or control needed to optimise
performance.

1.3.2 Classification of Statistical Methods

By now you may have realised that effective decisions have to be based upon realistic data. The
field of statistics provides the methods for collecting, presenting and meaningfully interpreting
the given data. Statistical Methods broadly fall into three categories as shown in the following
chart.

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