Consumer Reports magazine collected data for the fuel efficiency of cars (miles per gallon) compared to weight (thousands of pounds). The regression model below was created.
$y = 49 - 8.4x$
$r = -0.903$

1. Calculate and interpret $R$-squared in context.

   Hint (a):

   First calculate $R^2$ ($r^2$). Note that $R^2$% is the amount of variability that can be explained by a linear relationship.

   More Help (a):

   _____ percent of the variability in __________ can be explained by a linear relationship with _______.

   Answer (a):

   $81.5$
   fuel efficiency
   weight

2. Interpret the slope in context.

   Hint (b):

   Think about the units for the slope in this situation.