  Introduction

The three main measures of central tendency are mean, median and mode. Mode can be defined as the value that occurs most often in a series. Mode is that value of observation around which items are most densely concentrated. Mode can be calculated for individual series, discrete series and continuous series.

In case of individual series mode can be calculated by inspection method or by frequency distribution method. In case of discrete series Mode can be calculated in two ways: by Inspection Method and by Grouping Method. In case of continuous series first we ascertain the modal class and after that the exact value of mode is determined by using the formula. Value of mode can also be determined graphically with the help of Histogram.

While calculating mode we have to keep in mind some important observations relating to special types of problems like class intervals should be made equal in case of unequal class intervals and corresponding frequencies should also be adjusted accordingly.

According to Karl Pearson, asymmetrical distribution has an empirical relationship between mean, median and mode and one can estimate the value of mode as Mode = 3 Median – 2 Mean.

The merits of mode are: it is simple, it is unaffected by extreme values, for calculation we do not need complete data, etc. Demerits of mode are: it is uncertain, it is indeterminate, etc. To choose an average we should consider few points like the purpose of the study, capability for further statistical computations, etc. 