A company producing computer components has established that, on the average, a new employee can assemble N(t) components per day after t days of on-the-job training, as indicated in the following table (a new employee's productivity usually increases with time on the job, up to a leveling-off point). t 0 20 40 60 80 100 120 N(t) 9 50 67 75 80 83 84 (A) Find a quadratic regression equation for the data, and graph it and the data set in the same viewing window on your graphing calculator. The regression equation is y = (Round to ten decimal places as needed.) x+