Forecast project cost from actual and remaining hours

A project manager has spent hours and fresh estimates to finish three work packages. Calculate the forecast total and the variance from the approved budget.

SOURCE DATA
"work_package","actual_hours","remaining_hours","usd_per_hour","budget_usd"
"Design","10","4","60","900"
"Build","20","12","75","2200"
"Test","8","6","50","800"

RULES
Forecast cost = (actual hours + remaining hours) × the package rate. Rates are constant and include all costs in this fixture.
Remaining hours are estimates to finish, not the original planned hours.
Positive variance means over budget. Count an over-budget package only when its forecast strictly exceeds its budget.

MY FIGURES
Actual cost so far (USD): __________
Forecast total cost (USD): __________
Forecast minus budget (USD): __________
Over-budget packages: __________

MY REVIEW NOTE
________________________

METHOD
Design forecasts (10 + 4) × 60 = 840. Build forecasts (20 + 12) × 75 = 2400. Test forecasts (8 + 6) × 50 = 700.
Add package forecasts and package budgets independently, then subtract the budget total from the forecast total.
Identify Build as the only over-budget package; underspends on the other packages partly offset its 200 overrun.

REFERENCE ANSWERS — try first
Actual cost so far (USD): 2500. 600 + 1500 + 400 = 2500.
Forecast total cost (USD): 3940. 840 + 2400 + 700 = 3940.
Forecast minus budget (USD): 40. 3940 − (900 + 2200 + 800) = 40.
Over-budget packages: 1. Build exceeds its budget by 200; Design and Test are below budget.

Adding the original plan to actual cost double-counts completed work. Use an updated estimate of remaining work.

In a handoff, date the estimate-to-complete and name the assumptions behind remaining hours. A forecast is a current estimate, not a guarantee of final cost.

Occupational context: O*NET 31.0 Database, USDOL/ETA, Task 21469, occupation 13-1082.00. https://www.onetcenter.org/dl_files/database/db_31_0_csv/task_statements.csv
CC BY 4.0: https://creativecommons.org/licenses/by/4.0/
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