Example 10.2.1

y1={21, 21, 20.5, 23.5, 21.5, 20, 21.5, 23, 20, 16.5, 24.5};
y2={20, 21.5, 24, 24.5, 23, 21, 22.5, 23, 21, 19, 25};
y3={21.5, 24,  24.5, 25, 22.5, 21, 23, 23.5, 22, 19, 28};
y4={23, 25.5, 26, 26.5, 23.5, 22.5, 25, 24, 21.5, 19.5, 28};
B={ 1   1   1   1,
   -3  -1   1   3};
c={ 1  -1  -1   1,
  -1   3  -3   1};