In Professor Friedman's economics course, the correlation between the students total scores prior to the final exam and their final exam scores is r = 0.6. The pre-exam totals for all students in the course have mean 280 and standard deviation 30. The final exam scores have mean 75 and standard deviation 8.

a) Find the least squares regression line of final exam scores on pre-final total scores for this course. Show your work.

b) Julie's total before the exam was 300. What does LSR predict for her score on the final exam?

c) Should we have great confidence in our ability to predict Julie's final exam score accurately? Explain your answer and justify it statistically