Check the outliers. The plot that you generated in Exercise 10.83 has two observations that appear to be outliers.

(a) Identify these points on a plot of the data.

(b) Rerun the analysis with the other 12 hotels and summarize the effect of the two possible outliers on the results that you gave in Exercise 10.83.

10.86 Growth in grocery store size. Here are data giving the median store size (in square feet) by year for grocery stores:

Year Store size Year Store size Year Store size 1993 33.0 1998 40.5 2003 44.0 1994 35.1 1999 44.8 2004 45.6 1995 37.2 2000 44.6 2005 48.1 1996 38.6 2001 44.0 2006 48.8 1997 39.3 2002 44.0 2007 47.5

(a) Use a simple linear regression and a prediction interval to give an estimate, along with a measure of uncertainty, for the median grocery store size in 2008.

(b) Plot the data with the regression line. Based on what you see, do you think that the answer that you computed in part

(a) is a good prediction? Explain why or why not.