5.65 ● The article “Reduction in Soluble Protein and Chlorophyll Contents in a Few Plants as Indicators of Automobile Exhaust Pollution” (International Journal of Environmental Studies [1983]: 239–244) reported the following data on x 5 distance from a highway (in meters) and y 5 lead content of soil at that distance

(in parts per million):

x 0.3 1 5 10 15 20 y 62.75 37.51 29.70 20.71 17.65 15.41 x 25 30 40 50 75 100 y 14.15 13.50 12.11 11.40 10.85 10.85

a. Use a statistical computer package to construct scatterplots of y versus x, y versus log(x), log(y)

versus log(x), and 1

y versus 1

x

.

b. Which transformation considered in Part

(a) does the best job of producing an approximately linear relationship? Use the selected transformation to predict lead content when distance is 25 m.