» x=[60 40 80 30 60 40 90 80];
» y=[10 5 10 6 3 6 12 7];
» z=[78.2 45.4 100.0 35.7 80.5 42.8 120.4 90.5];
» xx = sum(x.*x)

xx =

       32200

» yy = sum(y.*y)

yy =

   499

» zz = sum(z.*z)

zz =

  5.0449e+004

» xz = sum(x.*z)

xz =

       40197

» xy = sum(x.*y)

xy =

        3840

» yz = sum(z.*y)

yz =

  4.7998e+003

» mean(z)

ans =

   74.1875

» sum(z)

ans =

  593.5000

» sum(x)

ans =

   480

» sum(y)

ans =

    59

» A=[xx xy sum(x), xy yy sum(y), sum(x) sum(y) 8]

A =

  Columns 1 through 6 

       32200        3840         480        3840         499          59

  Columns 7 through 9 

         480          59           8

» A=[xx xy sum(x); xy yy sum(y); sum(x) sum(y) 8]

A =

       32200        3840         480
        3840         499          59
         480          59           8

» inv(A)

ans =

    0.0005   -0.0024   -0.0127
   -0.0024    0.0267   -0.0556
   -0.0127   -0.0556    1.2996

» b=[zx; zy; sum(z)]
??? Undefined function or variable 'zx'.

» b=[xz; yz; sum(z)]

b =

  1.0e+004 *

    4.0197
    0.4800
    0.0594

» inv(A)*b

ans =

    1.3067
    0.4813
   -7.7611