Chapter 15 - Statistics

Statistics is the science which studies the methods and techniques used in the collection, presentation and analysis of data and draws. conclusion on the basis of the same. The statistics is thus, used in two senses:

1. In the sense of data and
2. In the sence of science.

In this portion we shall learn the pictorial representation of data such as Pie charts, the mean of grouped data and primary idea of probability.

Pictorial Representation of data:

Some times different. Charts are drawn to interprete any data. They are:

(i) Histogram
(ii) Frequency polygon
(iii) Frequency curve
(iv) Bar diagram
(v) Line graph
(vi) Pictograph and
(vii) Pie charts

We shall study on the pie charts in this section and illustrate with example:

Example 1. The number of students in a hostel speaking different languages are given below. Represent the data as a pie chart.

Language	Bengali	Hindi	English	Marathi	Tamil
Number of students	40	12	4	9	7

Solution:- The following table gives the share of each language as component of 360⁰.

Language	Number of students	Share as a component of 3600
Bengali	40	40 X 3600/72 = 2000
Hindi	12	12 X 3600/72 = 600
English	4	4 X 3600/72 = 200
Marathi	9	9 X 3600/72 = 450
Tamil	7	7 X 3600/72 = 350
Total	72	3600

Now we shall draw a circle of any convenient radius. First of all we shall fixed a sector of central angle 200⁰ depending on the share of Bengali language. Similarly, sectors of other languages are marked.