The following table presents measurements of hard- ness (in durometers) for tire treads containing various percentages of reclaimed rubber.
a. Construct a scatterplot of hardness (y) versus percent reclaimed rubber (x).
b. Compute the least-squares line for predicting hardness from percent reclaimed rubber.
c. If two tires differ in the amount of reclaimed rubber by 15%, by how much would you predict their hardnesses to differ?
d. The table shows that a tire that had 30% reclaimed rubber had a hardness of 67.3. If another tire was manufactured with 30% reclaimed rubber, what would you predict its hardness to be?
e. For what percent reclaimed rubber would you predict a hardness of 65?