Question

what are the concepts and uses of measures of Variability

Answer 1

heya..

Definitions of Variability:

Dictionary of Education—C.V. Good. “The scatter or variability of the observations of a distribution about some measure of central tendency.” 
Need of Variability:

1. Helps to as-certain the measures of deviation:

The measures of variability help us to measure the degree of deviation, which exist in the data. By that can determine the limits within which the data will navy in some measureable variety or quality.

2. It helps to compare different group:

ADVERTISEMENTS:

With the help of measures of validity we can compare the original data expressed in different units.

3. It is useful to supplement the information provided by the measures of central tendency.

4. It is useful to calculate further advance statistics based on the measures of dispersion.

Measures of Variability:

There are four measures of variability:

1. The Range

2. The Quartile Deviation

3. The Average Deviation

4. The Standard Deviation

These are:

1. The Range:

Range is the difference between in a series. It is the most general measure of spread or scatter. It is a measure of variability of the varieties or observation among themselves and does not given an idea about the spread of the observations around some central value.

Range = H—L

Here H = Highest score

L = Lowest score

Example:

In a class, 20 students have secured the marks as following:

22, 48, 43, 60, 55, 25, 15, 45, 35, 68, 50, 70, 35, 40, 42, 48, 53, 44, 55, 52

Here—The Highest score is 70

The Lowest score is 15

Range = H — L = 70 –15 = 55

If the range is higher than the group indicates more heterogeneity and if the range is lower than the group indicates more homogeneity. Thus range provides us an instant and rough indication of the variability of a distribution.



hope helped..