5.3.1. Segregation of the reference values into suitable groups

The corresponding reference values and the reference individuals should be segregated into suitable groups according to age, sex, etc. It is done with the purpose of reducing biological "noise" and variations among the people. Various authors have developed various criteria for segregation and statistical methods for this purpose [7].

#### 5.3.2. Assessment of the dispersal of each group

Graphical representation of the dispersal of each group should be done, and the data should then be assessed.

#### 5.3.3. Finding out the outliers

An outlier means a person or thing situated away or detached from the main body or system or a person or thing differing from all other members of a particular group or set. In Ref. value setup, it means a value which is incorrect or inaccurate that drifts or digresses from the established or accepted reference values. Too many methodical problems arise during the determination of the outliers; some methods developed in 2005 seems to be the solution for it [8].

#### 5.3.4. Establishment of the reference limits

Many parametric and nonparametric methods are available for this [6–9].
