These slides describe measures of dispersion. Very detail explanation on these slides. I hope students get more benefits about it.

1. Measures of Dispersion
Dr. Liaquat Ahmad
Associate Professor/Chairman
Department of Statistics and Computer Science

2. Measures of dispersion
Definition:
A measure of dispersion/variability/scatter indicates
the scattering of data. It explains the disparity of
data from one another, delivering a precise view of
their distribution. The measure of dispersion
displays and gives us an idea about the variation and
the central value of an individual item.
In other words, dispersion is the extent to which
values in a distribution differ from the average of
the distribution. It gives us an idea about the extent
to which individual items vary from one another,
and from the central value.

3. Types of Measures of Dispersion

4. Main Measures of Dispersion
1. Range
2. The Semi-Interquartile Range or Quartile
Deviation
3. Mean Deviation or Average Deviation
4. Variance
5. Standard Deviation

5. Relative Measure of Dispersion
The relative measures of dispersion are used to
compare the distribution of two or more data
sets. This measure compares values without
units. Common relative dispersion methods
include:
1. Co-efficient of Range
2. Co-efficient of Quartile Deviation
3. Co-efficient of Mean Deviation
4. Co-efficient of Variation
5. Co-efficient of Standard Deviation

6. Example: Calculate Range and coefficient of Range for the
following data
1, 3,5, 6, 7
Range = 7 - 1= 6
Coefficient of Range =