An equation was used to predict possible sales of phones for 6 months. The actual sales of phones are also listed. Actual sales 55 150 325 510 780 990 Predicted sales 40 150 300 500 800 1,000. The sum of the residuals is ______.
The residue in each case is the difference between actual and predicted sales. Thus: 55 - 40 = 15 150 - 150 = 0 325 - 300 = 25 510 - 500 = 10 800 - 780 = 20 1000 - 990 = 10 These add up to be: 15 + 25+ 10 +20 +10 = 80
