Hello all,

I'm styudying for PMP exam and i have some things that i want to make them clear, please help me with your knowledge:

1. I saw on Rita and on Kim Heldman book PERT and three point estimate. PERT divide everything by 6 and multiply most likely value with 4 and three point estimate divide everything by 3. How should i know in what situations to use them?

2. What roles is playing the PM during project initiation,planning and executing? ex: coaching,directing.