Answer:
20
Step-by-step explanation:
To calculate the sum of the residuals, subtract the predicted sales from the actual sales in the table below.
Actual sales 55 150 325 510 780 990
Predicted sales 40 150 300 500 800 1,000
This will show the change between them. Add each residual to find the sum.
55 - 40 = 15
150 - 150 = 0
325 - 300 = 25
510 - 500 = 10
780 - 800 = -20
990 - 1000 = -10
These add up to be 15 + 25+ 10 +-20 +-10 = 20