A mechanic was interested to see how a car engine's horsepower impacts the car's mpg fuel efficiency. The mechanic used to following information to construct a linear regression line that relates horsepower (independent variable) and mpg (dependent variable) The sample of cars had a mean horsepower of 286 and mean mpg of 28. The sample standard deviation for horsepower was 148 and sample standard deviation for mpg was 13 The correlation between horsepower and mog is -0.61. Calculate the slope of the linear regression fine. (round your final answer to two decimal places)