The following data were collected during a study of consumer buying patterns: 
 observation 
 x 
 y 
 observation x 
 y 
 1 
 15 
 74 
 818 
 78 
 2 
 25 
 80 
 914 
 70 
 3 
 40 
 84 
 1015 
 72 
 4 
 32 
 81 
 1122 
 85 
 5 
 51 
 96 
 1224 
 6 
 47 
 95 
 1333 
 90 
 7 
 30 
 83 
 a. plot the data. 
 b. obtain a linear regression line for the data. 
 c. what percentage of the variation is explained by the regression line? 
 d. use the equation determined in part b to predict the expected value of y for x = 41.