e.g. If there is a set of numbers, 3,5,5,7, & 10, what can be the representative number?
Suppose there are five children, each 3, 5, 5, 7, and 10 years old. When talking to these five children, it is desirable to assume the 5-year-old child is your audience and talk in the kid's level.

-> The way of choosing a representative number varies according to your purpose.
* Arithmetic mean
Obtained by dividing the sum of a set of quantities by number of quantities in the set. : 6

* Geometric mean
An avaerage calculated by multiplying a set of numbers and taking the nth root : 5.55
: Used when the set has high numbers.

* Median
The middle number of series arranged in numerical order : 5
: Other number than the median cannot be used

* Mode
A number most frequently occurs in the set: 5