assignable variance

Im having doubts on a couple of questions:

1. An example of assignable variance in quality control:

a. equipment problem

b. Person responsible

c. Identifiable problem

d. Inadequate resource

2. changes are made to cost baseline when :

a. There is variance between what is budgeted and what is spent

b. In response to approved changes

3. CPM ( overestimates,underestimates).project duration and PERT (overestimates,underestimates) project duration.

Please help on these questions with explanations.

  • Answer to 1:    'C' Identifiable problem

  • Answer to 2:    'B' In response to approved changes

  • Answer to 3:  CPM and PERT maybe same but PERT is applied when weightage is consideration...

Maybe 'admin' and others can help better in this.