Calculations :
Discrete Series : There is a difference
in the methods for finding the arithmetic means of the individual
series and a discrete series. In the discrete series, every term
(i.e. value of x) is multiplied by its corresponding frequency (f_{i}x_{i})
and then their total (sum) is found .
The arithmetic mean is then obtained by dividing the total frequency
by
the above sum so obtained
.
Therefore, if the observations x_{1} + x_{2} + x_{3} + .......+ x_{n} are repeated f_{1} + f_{2} + f_{3} + ......+ f_{n} times, then we have :
Arithmetic mean
The formulae for Arithmetic mean by direct method and by the shortcut methods are as follows:
Direct method Shortcut method
and u = x_{i}  A
Therefore,

Index
4.1 Introduction
4.2 Arithmetic Mean
4.3 Properties of Arithmetic Mean
4.4 Median
4.5 Mode
4.6 Empirical relation between mean, median & mode
Chapter 5
