Page 4 - lesson notes 60 xi MOD m.d & s.d

Standard Deviation
Standard deviation is the square root of the arithmetic mean of the squares of
deviations of the items from their mean values. It is often expressed by the lower
case of Greek letter sigma

Coefficient of Standard Deviation
This is a relative measure of the dispersion of series.

Coefficient of standard deviation (Coefficient of σ) =

(i) Calculation of Standard Deviation (Individual series)
(a) Direct Method

Here, σ = Standard Deviation;
2
ΣX = Sum total of the squares of deviation,
= Mean Value,
= Deviation from mean value;