If a regression of the yield per acre of corn on the quantity of fertilizer used is estimated using fertilizer quantities in the range typically used by farmers, the slope of the estimated regression line will certainly be positive. However, it is well known that, if an enormously high amount of fertilizer is used, corn yield will be very low. Discuss the benefits of applying regression analysis to a data set that includes a few cases of excessive fertilizer use combined with data from typical operations.