No aminophylline  With aminophylline
 x_1  x_2   y        x_1 x_2   y
 265  32   9.2       252  35  19.1
 348  35  19.3       411  35  20.1
 244  43  16.9       229  36  08.1
 618  41  22.1       761  29  35.6
 434  44  15.6       541  40  22.1
 432  28  10.9       313  38  24.7
 790  48  16.7       873  52  21.0
 245  43  13.0       359  45  14.9
 348  36  20.9       433  32  18.3