Variance for frequency distribution for JEE

Formula

\(\sigma^2=\frac{1}{N}\sum f_i(x_i-\bar{x})^2\)

Variables: \(x_i\): values or class marks, \(f_i\): frequencies, \(\bar{x}\): mean, \(N=\sum f_i\).

Conditions: For grouped data use class marks.

Variance of discrete/grouped data.