The following data were collected on specific gravity and spectrophotometer analysis for 26 mixtures of NG (nitroglycerine), TA (triacetin), and 2 NDPA (2-nitrodiphenylamine). y (Specific Mixture X (% NG) X2 (% TA) X3 (% 2 NDPA) Gravity) 79.98 19.85 0 1.4774 80.06 18.91 1.00 1.4807 80.10 16.87 3.00 1.4829 77.61 22.36 0 1.4664 77.60 21.38 1.00 1.4677 77.63 20.35 2.00 1.4686 JE ODOVA VIA WNA 77.34 19.65 2.99 1.4684 75.02 24.96 0 1.4524 75.03 23.95 1.00 1.4537 74.99 22.99 2.00 1.4549 74.98 22.00 3.00 1.4565 72.50 27.47 0 1.4410 13 72.50 26.48 1.00 1.4414 14 72.50 25.48 2.00 1.4426 15 72.49 24.49 3.00 1.4438 16 69.98 29.99 0 1.4279 69.98 29.00 1.00 1.4287 18 69.99 27.99 2.00 1.4291 19 69.99 26.99 3.00 1.4301 20 67.51 32.47 0 1.4157 21 67.50 31.47 1.00 1.4172 22 67.48 30.50 2.00 1.4183 23 67.49 29.49 3.00 1.4188 24 64.98 34.00 1.00 1.4042 25 64.98 33.00 2.00 1.4060 26 64.99 31.99 3.00 1.4068 Source: Raymond H. Myers, Technometrics, vol. 6, no. 4 (November 1964): 343-356. There is a need to estimate activity coefficients from the model 1 y= BIX + Bix2 + Bax3 The quantity parameters B1, B2, and B, are ratios of activity coefficients to the individual specific gravity of the NG, TA, and 2 NDPA, respectively. a. Determine starting values for the model parameters. b. Use nonlinear regression to fit the model. c. Investigate the adequacy of the nonlinear model