The percent y of U. S. college freshmen who identified computer science as their probable field of study from 2001 to 2005 decreased in a pattern that was approximately parabolic. The least squares regression parabola y = at² + bt + c for the data is found by solving the system
5c + 15b + 55a = 9.7
15c + 55b + 225a = 23.9
55c +225b + 979a = 77.3
Let t represent the year, with t=1 corresponding to 2001.​