Retail chain Kroger has more than 2700 locations and is the largest supermarket in the United States based on revenue. Kroger has invested heavily in data, technology, and analytics. Feeding predictive models with data from an infrared sensor system called QueVision to anticipate when shoppers will reach the checkout counters, Kroger is able to alert workers to open more checkout lines as needed. This has allowed Kroger to lower its average checkout time from four minutes to less than 30 seconds (Retail Touchpoints). 32 observations measured in minutes before 6 p.m.

A.) Using the entire data set, develop the estimated regression equation that can be used to predict the shopping time given the arrival time (to decimals).

B.) After looking at the scatter diagram in part (a), suppose you were able to visually identify what appears to be an influential observation. Drop this observation from the data set and fit an estimated regression equation to the remaining data (to decimals).

C.) Compare the estimated slope for the new estimated regression equation to the estimated slope obtained in part (c). Does this approach confirm the conclusion you reached in part (d)? Explain.

The slope of the estimated regression equation is now as compared to a value of when this observation is included. Thus, we see that this observation