# Standard Deviation

As we are aware that statistics is the collection of data where we find represent them graphically to study it,. Also we find the mean, median, mode of the given data which will help us to study more about the given data. There are different methods of calculating the mean, median and mode, and each time we arrive at approximately the same result whatever be the method we adopt for.

The mean or average does not tell the full story. It is hardly full representative of a mass unless we know the manner in which the individual items scatter around it. A further description of the series is necessary if we have to gauge how representative the average is. Thus the measures of central tendency must be supported and supplemented by some other measures called Dispersion.

The basic dispersions are range and quartile deviation. As they are not based on all the observations and also they do not exhibit any scatter of the observations from an average and completely ignore the composition of the series we have the Mean Deviation and the Standard Deviation. In this section let us study about the Standard Deviation.