Q₁ represents:

    is  used  to calculate:

Semi- inter quartile range is also known as:

Co-efficient of quartile deviation is calculated by applying following formula:

For standard deviation, the relative measure is called

Co-efficient of variation is located by applying following formula:

Middle value of series is known as:

L- S is the formula of calculating:

 The concept of Lorenz curve was developed by:

_________ and______ are based upon deviation of values from the average.