|Best significant term polynomial (default)
||Fits a 2nd- and 3rd-order polynomial fit, then determines if either are better than the linear fit by testing whether the nonlinear terms (polynomial fit coefficients) are statistically significant. The 3rd-order polynomial is used if it has significant nonlinear terms, the 2nd-order polynomial is used if it has significant nonlinear terms, otherwise the measurement procedure is assumed to be linear. Recommended by CLSI EP6.
|Forward stepwise polynomial LoF
||Fits a linear fit and performs a lack-of-fit (LoF) significance test to determine how well the model fits the data. If the fit is significantly worse than expected, a 2nd-order polynomial is fit and the LoF test is repeated. If the 2nd-order polynomial fit is not significantly worse, it is used, otherwise a 3rd-order polynomial is fit. Recommended by Liu and others.
||Fits a polynomial model of given order.