Mathematics-Average

Average is a measure to calculate the middle of the particular data set. The data set is list of numbers, or characters etc. . If the numbers in the set are same, then the average is number or character itself. 
                 
Average is calculated using (sum of observations) / (No: of observations). [ Note :: Sum of observation means sum of list of numbers or list of characters.]
                 
Suppose a man covers certain distance at x kmph and an equal distance at y kmph. Then average speed during the whole journey is 2xy / (x + y)

Eg ::) Calculate the average of numbers between 1 to 5
         (2 + 3 + 4) / 3 = 9 / 3 = 3
         ie In between 1 and 5 there are only 3 numbers present. So no : of observation is 3.

Average is also called measure of central tendency. In the area of statistics, arithmetic mean, median and mode are used to calculate central tendency of data items. 

The three most common averages are 

1) Arithmetic Mean (AM)

2)Geometric Mean (GM)

3)Harmonic Mean (HM)