求高手解释
Estimation Command:
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LS LOG(Y) C PDL(LOG(X),7,2)

Estimation Equation:
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LOG(Y) = C(1) + C(2)*PDL01 + C(3)*PDL02 + C(4)*PDL03
其中C(1)=6.709491,C(2)=0.024444,C(3)=-0.019882,C(4)=0.006137.
Forecasting Equation:
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LOG(Y) = C(1) + C(5)*LOG(X) + C(6)*LOG(X(-1)) + C(7)*LOG(X(-2)) + C(8)*LOG(X(-3)) + C(9)*LOG(X(-4)) + C(10)*LOG(X(-5)) + C(11)*LOG(X(-6)) + C(12)*LOG(X(-7))

Substituted Coefficients:
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LOG(Y) = 6.70949110194 + 0.139319431808*LOG(X) + 0.0887540174642*LOG(X(-1)) + 0.050462065032*LOG(X(-2)) + 0.0244435745113*LOG(X(-3)) + 0.010698545902*LOG(X(-4)) + 0.00922697920435*LOG(X(-5)) + 0.0200288744182*LOG(X(-6)) + 0.0431042315435*LOG(X(-7))

LOG(X)前的系数0.139319431808怎么来的，为什么不等于C(2)?