4.12 I FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICSStatistical Representation of Data
can be determined by locating the abscissa of the point on the curve, whose cumulative frequency is N/2.
Similarly, the abscissa of the points on the less than type corresponding to the cumulative frequencies N/4
and 3N/4 give the Q 1 (first quartile) and Q 3 (third quartile) respectively, (Q1, Q3 will be discussed after
median in the chapter of Average).
Ogive (less than type) of given data :From the above graph we find that Q 3 = 53 (approx).
Circular Diagram (or Pie diagram) : It is a pictorial diagram in the form of circles where whole area
represents the aggregate and different sectors of the circle, when divided into several parts, represent the
different components.
For drawing a circular diagram, different components are first expressed as percentage of the whole. Now
since 100% of the centre of a circle is 360 degrees. 1% corresponds to 3.6 degrees. If p be the percentage
of a certain component to the aggregate, then (p × 3.6) degrees will be the angle, which the corresponding
sector subtends at the centre.
Note : A pie diagram is drawn with the help of a compass and a diagonal scale or a protractor. Different
sectors of the circle representing different components are to be marked by different shades or signs.
Example 10: The expenditure during Second Five-year Plan in West Bengal is shown as below :
(` in Crores)
On Industries 127.00
” Irrigation 92.50
” Agriculture 100.00
” Transports & Roads 92.50
” Miscellaneous 68.00
480.00