Jiffy Print is a printing shop on a local college campus. In analyzing the costs over a two-year period, the following data was available for the printing jobs on the colour printer:

Required:
1. Prepare a scattergraph based on these data. Plot cost on the vertical axis and number of jobs on the horizontal axis.
2. Compute the cost formula for print jobs using the method of least squares. Using the regression cost formula, what is the predicted cost for a month with 250 jobs?
3. Comment on the usefulness of the least squares approach in these circumstances and whether additional value has been added by using regression analysis

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Month Cost (S) Jobs January February March 1,588 2,143 2,005 1,908 2,163 175 295 260 April May June July August September October 245 305 1,478 1,458 1,613 1,708 1,348 1,428 1,638 155 145 175 195 205 November 225 December 255 1,840 1,728 1,543 1,940 1,860 1,590 1,513 1,633 1,928 2,028 1,850 2,038 230 January February March 285 265 April May June 250 230 220 July August September 225 235 265 285 October November 300 December 275