2. Suppose you now wanted to calculate duration estimates for these activities. How would you make use of the following approaches? Are some more useful than others? i. Expert opinion ii. Past history iii. Mathematical derivation

  Suppose you now wanted to calculate duration estimates for these activities. How would you make use of the following approaches? Are some more useful than others?

i. Expert opinion

ii. Past history

iii. Mathematical derivation

APA format, please also use references from outside, 500 words, please in 1 hr