How to use regression to find equation of data set?

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Jenifer NG
Jenifer NG 2022-11-3
评论： Jenifer NG 2022-11-6
Ran in:
Dear All,
I would like to ask for some help.
I am trying to find the equation present my data.
But io stuck when use regression method.
could someone help me?
i assume my equation is:
z = a*x^n +b*y+c
Thanks so much!
Han
x = [12 12.5 13 13.5 14
]
x = 1×5
12.0000 12.5000 13.0000 13.5000 14.0000
y = [61 61.5 62 62.5 63
]
y = 1×5
61.0000 61.5000 62.0000 62.5000 63.0000
z = [120 114 103 93 80
124 120 109 97 85
128 121 113 101 88
130 125 116 105 92
134 128 119 109 96
]
z = 5×5
120 114 103 93 80 124 120 109 97 85 128 121 113 101 88 130 125 116 105 92 134 128 119 109 96
surf(x,y,z)

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采纳的回答

KSSV
KSSV 2022-11-3
Ran in:
x = [12 12.5 13 13.5 14] ;
y = [61 61.5 62 62.5 63] ;
[X,Y] = meshgrid(x,y) ;
Z = [120 114 103 93 80
124 120 109 97 85
128 121 113 101 88
130 125 116 105 92
134 128 119 109 96] ;
x = X(:) ;
y = Y(:) ;
z = Z(:) ;
sf = fit([x, y],z,'poly22')
Linear model Poly22: sf(x,y) = p00 + p10*x + p01*y + p20*x^2 + p11*x*y + p02*y^2 Coefficients (with 95% confidence bounds): p00 = -3160 (-6274, -46.38) p10 = 55.49 (9.233, 101.7) p01 = 90.67 (-8.557, 189.9) p20 = -4.514 (-5.311, -3.717) p11 = 0.68 (0.01303, 1.347) p02 = -0.7429 (-1.54, 0.05432)
plot(sf,[x y],z)
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KSSV
KSSV 2022-11-5
Ran in:
x = [12 12.5 13 13.5 14] ;
y = [61 61.5 62 62.5 63] ;
[X,Y] = meshgrid(x,y) ;
Z = [120 114 103 93 80
124 120 109 97 85
128 121 113 101 88
130 125 116 105 92
134 128 119 109 96] ;
x = X(:) ;
y = Y(:) ;
z = Z(:) ;
sf = fit([x, y],z,'poly22')
Linear model Poly22: sf(x,y) = p00 + p10*x + p01*y + p20*x^2 + p11*x*y + p02*y^2 Coefficients (with 95% confidence bounds): p00 = -3160 (-6274, -46.38) p10 = 55.49 (9.233, 101.7) p01 = 90.67 (-8.557, 189.9) p20 = -4.514 (-5.311, -3.717) p11 = 0.68 (0.01303, 1.347) p02 = -0.7429 (-1.54, 0.05432)
zi = sf(x,y) ;
figure
hold on
surf(X,Y,Z)
plot3(x,y,zi,'*b')
view(3)

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