Use a spreadsheet to complete the following tasks:

1. Using the least-squares method, calculate a and b for all the three variables
2. Calculate the correlation coefficient, the coefficient of determination and explain what they mean for all three variables.
3. Using the values calculated in task 1, calculate how many employees, units or labour hours would have been incurred if the total cost was 875 000.
4. Use the values calculated in task 1 to demonstrate how these con be used to forecast the total cost for 13 312 units, 500 employees and 522 341 labour hours.

Research and presentation

Using Powerpoint, provide the following:

After viewing your calculation in task 4, Mrs Ruva Tamic noticed that they give very similar values. She is now confused which of the three variables would be best use for forecasting the total cost.

5. Select and explain which is the best estimator for acquiring the forecast of the total cost from the independent variables of X1, X2 and X3.
6. Use Graphs to demonstrate the concept of correlation and support your choice of variable.

Output (X1) (Units) Month August September October November December January February March April May June July Sum= No. OF Direct Labour (X3) Total Cost Employees (X2) (Hours) Y () 902 90 5436 234987 950 85 5643 265432 987 100 6543 276543 1250 105 7765 245321 1342 103 7632 276890 1423 110 8765 296754 1987 123 9765 271298 2321 140 11765 310456 750 78 4509 230000 2665 150 12564 312453 2210 118 10543 306587 2342 115 10123 304576 19129 1317 101053 3331297 Output (X1) (Units) Month August September October November December January February March April May June July Sum= No. OF Direct Labour (X3) Total Cost Employees (X2) (Hours) Y () 902 90 5436 234987 950 85 5643 265432 987 100 6543 276543 1250 105 7765 245321 1342 103 7632 276890 1423 110 8765 296754 1987 123 9765 271298 2321 140 11765 310456 750 78 4509 230000 2665 150 12564 312453 2210 118 10543 306587 2342 115 10123 304576 19129 1317 101053 3331297