3. (15 points) The median starting salary for new law school graduates (salary) is determined by: log( salary) = 8.34+ 0.245GPA + 0.038log(cost) n =136, R? = 0.842 where GPA (measured in points) is the median college GPA for the class and cost (measured in dollars) is the annual cost of attending law school (a) Interpret the coefficient on the variable GPA clearly (b) Interpret the coefficient on the variable log(cost) clearly (c) Explain the meaning of R? = 0.842 clearly