Measure of Central values
The choice of the suitable measure depends on the two factors
1. The type of data available
If there generally acute avoid the mean deviations as well. If they have gaps around the quartiles the bottle division should be avoided. If there are open-end classes the quartile measure of dispersion should be praying for. If if they are generally rescued and dfu in number or contain extreme value avoid the standard deviation.
|Measure of dispersion|
2. The purpose of investigation
vishwa make use of standard deviation for measuring variability.in an elementary treatment of statical series in which a measure of variability is desired only for itself any of three measures, namely range quartile deviation and average deviation would be acceptable. Probably the average deviations would be better.howrah in usual practise the measure of variability is employed in for the statistical analysis. It is free from those defects from which other measures.it lends itself to the analysis of variability in term of normal call of error.Practically all advanced statistical methods deal with variability and centre around the standard deviation.