When water flows across farmland, some of the soil is washed away, resulting in erosion. Researchers released water across a test bed at different flow rates and measured the amount of soil washed away. The following table gives the flow (in liters per second) and the weight (in kilograms) of eroded soil:

Flow rate 0.31 0.85 1.26 2.47 3.75
Amount of eroded soil 0.82 1.95 2.18 3.01 6.07

(a) Use your calculator to find the equation of the least-squares regression line. Be sure to define any variables you use.

(b) Researchers would like to predict what would happen under extreme conditions. Would it be reasonable to use this equation to predict the amount of soil washed away if the flow rate were 6 liters per second? Explain.


(c) Calculate and interpret the residual for the flow rate of 3.75 liters per second.