Obtain a plot of the data of Exercise 11.86 with sales plotted against density. Does it ­appear that straight- line prediction makes sense?
In exercise

Sales S4 2 54 62 72 83 115 90 66 60 100 78 152 87 54 82 Density 6.5 4.6 55 46 4.2 4.3 2.3 35 32 84 34 4.0 20 3.2 6.7 3.0 Sales 59 183 171 96 134 79 94 82 66 62 45 69 65 81 94 117 Density 5.7 13 13 3.0 2.2 43 26 3.0 43 78 94 42 5.9 6.2 2.8 24