Statistics – Notes

Introduction to Dispersion

Statistics is a branch of mathematics that deals with the collection, classification and analysis of numerical data.

Statistics that signify the extent of the spread of items around the measure of the central tendency is known as dispersion.

The range of distribution is the difference between the greatest and the least values observed.

Mean Deviation for Ungrouped Data

The deviation of an observation x from a fixed value k is equal to x – k.

Mean deviation about the mean = MD () =  , where  = mean.

Mean deviation about the median = MD (M) =  ,

Where M = median.