Lower prices for color laser printers make them a great alternative to inkjet printers. PC World reviewed and rated 10 color laser printers. The following data show the printing speed for color graphics in pages per minute (ppm) and the overall PC World rating for each printer tested (PC World, December 2005).

a. Develop a scatter diagram of the data using the printing speed as the independent variable.
Does a simple linear regression model appear to be appropriate?
b. Develop an estimated multiple regression equation with x = speed and x2 as the two independent variables.
c. Consider the nonlinear model shown by equation (16.7). Use logarithms to transform this nonlinear model into an equivalent linear model, and develop the corresponding estimated regression equation. Does the estimated regression equation provide a better fit than the estimated regression equation developed in part (b)?

Rating 83 81 79 78 Make and Model Speed (ppm) Dell 3000cn Oki Data C5200n Konica Minolta MagiColor 2430DL Brother HL-270OCN Lexmark C522n HP Color LaserJet 3600n Xerox Phaser 6120n Konica Minolta MagiColor 2450 HP Color LaserJet 2600n HP Color LaserJet 2550L 3.4 2.7 3.8 74 73 71 70 61