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Measures Of Dispersion

Question
CBSEENST11024828

What are the four alternative measures of absolute dispersion ? Discuss their properties.

Solution

The four alternative measure of absolute dispersion are:

(i) Range, (ii) Quartile Deviation, (iii) Mean deviation, (iv) Standard Deviation.

1. Features of the range :

(a) It is rigidly defined.

(b) It is easy to calculate and simple to interpret.

(c) It does not depend on all values of the variables.

(d) It is unduly affected by extreme values.

(e) The range depends on the units of measurement of the variable.

2. Features of Quartile deviation :

(a) It is rigidly defined.

(b) It is easy to calculate and simple to interpret.

(c) It does not depend on all values of the variable.

(d) The units of measurement of the quartile deviation are the same as those of the variable.

3. Features of mean deviation :

(a) It is rigidly defined.

(b) It depends on all values of the variable.

(c) It is based on absolute deviations from a central values.

(d) It is easy to understand.

(e) It involves harder calculations than the range and quartile deviation.

(f) It is amendable to algebraic treatment.

(g) The units of measurement of the mean deviation are the same as those of the variable.

4. Features of Standard deviation :

(a) It is the best measure of the variation because it is based every item of the series and further algebraic treatment is possible.

(b) It is not very much affected by fluctuation of sampling.

(c) It is the only measure for calculating combined standard deviation of two or more graphs.

(d) It is a definite measure of dispersion.