VARIANCE FOR GROUPED AND UNGROUPED DATA

Question 1 :

Calculate the variance of the following table.

x    2    4    6     8    10    12    14    16

f    4    4    5    15     8      5      4    5

Solution :

Σf  =  50 and Σfd²  =  804

σ²  =  √(Σfd²/Σf)

=  √(804/50)

=  16.08

Question 2 :

Find the variance of the following distribution

Solution :

Here we consider the first data that is class interval as (x) and no of frequency as (f).

Σfd² =  5425 and Σf  =  100

 σ  =  √(Σfd²/Σf)

=  √(5425/100)

=  √54.25

=   7.37

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