Study Note - 4
STATISTICAL REPRESENTATION OF DATA
FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICS I 4.14.1 DIAGRAMATIC REPRESENTATION OF DATA
4.1.1. Data:
A statistician begins the work with the collection of data i.e. numerical facts. The data so collected are
called raw materials (or raw data). It is from these raw materials, a statistician analysis after proper classification
and tabulation, for the final decision or conclusion. Therefore it is undoubtedly important that the raw data
collected should be clear, accurate and reliable.
Before the collection of data, every enquiry must have a definite object and certain scope, that is to say,
what information will be collected for whom it will be collected, how often or at what periodically it will be
collected and so on. If the object and the scope of enqiry are not clearly determined before hand, difficulties
may arise at the time of collection which will be simply a wastage of time and money.
4.1.2. Statistical Units:
The unit of measurement applied to the data in any particular problem is the statistical unit.
Physical units of the measurement like quintal, kilogramme, metre, hour and year, etc. do not need any
explanation or definition. But in some cases statistician has to give some proper definition regarding the
unit. For examples, the wholesale price of commodity. Now what does the form ‘wholesale price’ signify?
Does it stand for the price at which the producer sells the goods concrened to the stockist, or the price at
which the stockist sells to a wholesaler? Is it the price at which the market opened at the day of enquiry?
Many such problems may arise as stated. It is thus essential that a statistician should define the units of data
before he starts the work of collection.
4.1.3. Types of Methods of Collection of Data :
Statistical data are usually of two types :
(i) Primary, (ii) Secondary
Data which are collected for the first time, for a specific purpose are known as primary data, while those
used in an investigation, which have been originally collected by some one else, are known as secondary
data.
For example, data relating to national income collected by government are primary data, but the same
data will be secondary while those will be used by a different concern.
Let us take another example, known to everyone. In our country after every ten years counting of population
is done, which is commonly known as Census. For this data are collected by the Government of India. The
This Study Note includes
4.1 Diagramatic Representation of Data
4.2 Frequency Distribution
4.3 Graphical Representation of Frequency Distribution- Histogram
- Frequency Polygon
- Ogive
- Pie-chart