Mathematics · important
Assumed mean method for variance for JEE
Calculation of standard deviation, variance and mean deviation for grouped and ungrouped data
Formula
\(\sigma^2=\frac{\sum f_i d_i^2}{N}-\left(\frac{\sum f_i d_i}{N}\right)^2\), \(d_i=x_i-a\)
Variables: \(a\): assumed mean, \(x_i\): value/class mark, \(f_i\): frequency.
Conditions: For ungrouped/discrete/grouped data.
Simplified variance computation.