Question

Formula for standard deviation for frequency distribution

Answer 1

this is the formula for step deviation method...

* the classes of investment are written in the first column .

*the values of class marks are written in the second column.

* the values of

$d = x - a$

are written in the third column. (here x =the class mark and a,= the assumed mean.)

*the G. C. D. (greatest common divisor) of all values of D is taken and that value = g

*the corresponding frequencies are written in the fifth column.

*the product f x u for each class is written in the sixth column.

* the mean of u is found by the following formula.

$\frac{ }{u} = \frac{Σfu}{Σf}$

and the formula for step deviation is

$\frac{}{x} = a + \frac{}{u} \times g$