The Characteristic Polynomial of the Information Matrix for Second-Order Models
二阶模型信息矩阵的特征多项式
The characteristic polynomial is derived for the information matrix $M$ for those main-effect and second-order models based on fractions of the $3^n$ factorial which render the model symmetric under permutation of the factors. Explicit formulas for the determinant of $M$ and the trace of $M^{-1}$ result.