8. Why is it necessary to calculate the earned value of work performed? How is this done? 9. Give an example of calculating a cost performance index. What does it mean when the CPI is below 1.0? What does it mean when the CPI is above 1.0? 10. What does it mean when cost variance is negative? What does it mean when cost variance is positive? When evaluating a work package with a negative cost variance, on what two types of activities should you focus? Why? 11. What is the key to managing cash flow? How can this goal be accomplished? 12. a. Refer to the table below. What is the cumulative budgeted cost at the end