10. Lexus, Inc. The Lexus GX is a midsize sport utility vehicle (SUV) sold in North American and Eurasian markets by Lexus. The sales of the Lexus GX 470 from 2003 to 2017 are given in the table

a. Plot the data using a scatterplot. How would you describe the relationship between year and sales of the Lexus GX 470?

b. Even though the scatterplot in part a might indicate differently, assume that the relationship between year and sales is linear. Find the least-squares regression line relating the sales of the Lexus GX 470 to the year being measured.

c. Is there sufficient evidence to indicate that sales are linearly related to year? Use a 5.05.

d. Examine the diagnostic plots shown below. What can you conclude about the validity of the regression assumptions?

e. Based on your conclusions in part

d, is it advisable to predict the 2018 sales using the regression line from part b? Explain.

Transcribed Image Text:

Year Sales Year Sales 2003 31,376 2011 11,609 2004 35,420 2012 11,039 2005 34,339 2013 12,136 2006 25,454 2014 22,685 2007 23,035 2015 25,212 2008 16,424 2016 25,148 2009 6,235 2017 27,190 2010 16,450