Suppose the following costs and units of work completed were recorded on an activity:

Month	Monthly Expenditure	Number of Work Units Completed
1 2 3 4 5 6	$1,200 $1,250 $1,260 $1,280 $1,290 $1,280	30 32 38 42 42 42

Answer the following questions:

1. For each month, determine the cumulative cost, the cumulative work completed, the average cumulative cost per unit of work, and the monthly cost per unit of work.

2. For each month, prepare a forecast of the eventual cost-to-complete the activity based on the proportion of work completed.

3. For each month, prepare a forecast of the eventual cost-to-complete the activity based on the average productivity experienced on the activity.

4. For each month, prepare a forecast of the eventual cost-to-complete the activity based on the productivity experienced in the previous month.

5. Which forecasting method (b, c or d) is preferable for this activity? Why?