Mathematics · essential
Computational formula for variance for JEE
Calculation of standard deviation, variance and mean deviation for grouped and ungrouped data
Formula
\(\sigma^2=\frac{\sum f_i x_i^2}{N}-\left(\frac{\sum f_i x_i}{N}\right)^2\)
Variables: \(x_i\): values or class marks, \(f_i\): frequencies, \(N=\sum f_i\).
Conditions: For ungrouped data, take all \(f_i=1\).
Fast variance calculation.