The mean deviation and the standard deviation have the same units in which the data are given. Whenever we want to compare the variability of two series with same mean, which are measured in different units, we do not merely calculate the measures of dispersion but we require such measures which are independent of the units. The measure of variability which is independent of units is called coefficient of variation (denoted as C.V.)
The coefficient of variation is defined as
`C.V =σ/bar x xx 100 , bar x ≠ 0 `,
Shaalaa.com | Analysis of Frequency Distribution
Find the mean, mode, S.D. and coefficient of skewness for the following data:
|No. of persons (cumulative):||15||32||51||78||97||109|
Calculate coefficient of variation from the following data:
|Income (in Rs):||1000-1700||1700-2400||2400-3100||3100-3800||3800-4500||4500-5200|
|No. of families:||12||18||20||25||35||10|
An analysis of the weekly wages paid to workers in two firms A and B, belonging to the same industry gives the following results:
|Firm A||Firm B|
|No. of wage earners||586||648|
|Average weekly wages||Rs 52.5||Rs. 47.5|
|Variance of the
|distribution of wages|
(i) Which firm A or B pays out larger amount as weekly wages?
(ii) Which firm A or B has greater variability in individual wages?
The following are some particulars of the distribution of weights of boys and girls in a class:
|Mean weight||60 kg||45 kg|
Which of the distributions is more variable?