PC World rated four component characteristics for 10 ultraportable laptop computers: features; performance; design; and price. Each characteristic was rated using a 0–100 point scale. An overall rating, referred to as the PCW World Rating, was then developed for each laptop. The following table shows the performance rating, features rating, and the PCW World Rating for the 10 laptop computers (PC World website, February 5, 2009).

a. Determine the estimated regression equation that can be used to predict the PCW World Rating using the performance rating as the independent variable.

b. Determine the estimated regression equation that can be used to predict the PCW World Rating using both the performance rating and the features rating.

c. Predict the PCW World Rating for a laptop computer that has a performance rating of 80 and a features rating of 70.