Question

The formula to find mean from a grouped frequency table is $X=A+\frac{\sum f_i{u}_i}{\sum f_i}\times hg$ . In the formula, $u_i=................$

• A. $\frac{x_i+A}{g}$
• B. $(x_i-a)$
• C. $\frac{x_i-A}{h}$
• D. $\frac{A-x_i}{g}$

Answer 1

The correct option is C $\frac{x_i-A}{h}$

The formula is stated wrong. The

correct formula to calculative mean

from grouped frequency table is

$X=A+(\frac{\sum f_i{u}_i}{\sum f_i}\times h)$

where, A = Assumed mean

h= class interval length

$f_i=$ frequency of each class

and $u_i=\frac{di}{h}$

where $d_i$ is the difference between

assumed mean and the mid element

in a class.

i.e., $d_i=xi-A$

Therefore , $u_i=\frac{x_i-A}{h}$

Option (C) looks correct.