Quantitative Analysis for Management, 13/e

Key Equations

1. (11-1)

   $$t=\frac{a+4m+b}{6}$$

   Expected activity completion time.

2. (11-2)

   $$\text{Variance}={\left(\frac{b-a}{6}\right)}^2$$

   Variance of activity completion time.

3. (11-3)

   $$\text{EF}=\text{ES}+t$$

   Earliest finish time.

4. (11-4)

   $$\text{LS}=\text{LF}-t$$

   Latest start time.

5. (11-5)

   $$\text{Slack}=\text{LS}-\text{ES}or\text{Slack}=\text{LF}-\text{EF}$$

   Slack time in an activity.

6. (11-6)

   $\text{Project} \text{variance}=\sum$ variances of activities on critical path

7. (11-7)

   $$\text{Z}=\frac{\text{Due} \text{date}-\text{Expected} \text{date} \text{of} \text{completion}}{{\sigma }_T}$$

   Number of standard deviations the target date lies from the expected date, using the normal distribution.

8. (11-8) Value of work completed = (Percentage of work completed) × (Total activity budget)

9. (11-9) Activity difference = Actual cost - Value of work completed

10. (11-10)

    $$\text{Crash} \text{cost/Time} \text{period}=\frac{\text{Crash} \text{cost}-\text{Normal} \text{cost}}{\text{Normal} \text{time}-\text{Crash} \text{time}}$$

    The cost in CPM of reducing an activity’s ...