Question:linear cost approximation

Bailey Nickles, managing director , is examining how overhead costs behave with changes in monthly professional labor - hours billed to clients assume the following historical data

total overhead costs professional labor- hours billed to clients

$340000 3000

400000 4000

435000 5000

47000 6000

529000 7000

587000 8000

required

1- compute the linear cost function relating total overhead cost to professional labor-hours using the representative observations of 4000 and 7000 hours plot the linear cost function does the constant component of the cost function represent the fixed overhead costs?why?

2- what would be the predicted total overhead costs for a- 5000 hours b- 8000 hours using the cost function estimated in requirement 1? plot the predicted costs and actual costs for 5000 and 8000 hours

3- nickles had a chance to accept a special job that would have boosted professional labour hours from 4000 to 5000 hours suppose nickles guided by the linear cost function rejected this job because it would have brought a total increase in contribution margin of $38000 before deducting the predicted increase in total overhead cost $43000 what is the actual total contribution margin forgone?