In a study nine tires of a particular brand were driven on a

In a study, nine tires of a particular brand were driven on a track under identical conditions. Each tire was driven a particular controlled distance (measured in thousands of miles) and the tread depth was measured after the drive. Tread depth is measured in “mils.” Here, 1 mil is 0.001 inch. The least-squares regression line was computed and added to a scatterplot of these data. On the plot, one data point is marked with an “X.”

The equation of the least-squares regression line is:

Tread depth = 360.64 – 11.39x (thousands of miles)

Also, r² = 0.953. The data value marked with “X” in the provided scatterplot has a:

Solution

at X=15 shown in graph

tread depth=360.64--(11.39x15) =189.79

positive value for the residual