• # question_answer The variance $\left( {{V}_{1}} \right)$ for critical path $a\to b=4$ time units, $b\to c=16$ units, $c\to d=4$ time units,      $d\to e=1$ time unit. The standard deviation of the critical path $a\to e$ is: A) 3                                 B) 4C) 5                                 D) 6

$\sigma =\sqrt{\sum{\text{variance}}}$ $=\sqrt{4+16+4+1}=\sqrt{25}=5$