The tendency of the observations to cluster in the central part of the data set is called central tendency and the summary value as a measure of central tendency. The measure of central tendency or location are generally known as averages. The most common types of averages are arithmetic mean, geometric mean, harmonic mean, mode and median. The best of tendency is arithmetic mean. It is defined as a value obtained by dividing the sum of all the observation by their number, that is

mean= [sum of all the observations]/[number of the observations]

Arithmetic mean is used because it is simple to understand and easy to interpret. It is quickly and easily calculated. It is amenable to mathematical treatments. It is relatively stable in repeated sampling experiments.

mean= [sum of all the observations]/[number of the observations]

Arithmetic mean is used because it is simple to understand and easy to interpret. It is quickly and easily calculated. It is amenable to mathematical treatments. It is relatively stable in repeated sampling experiments.