The RegressionOption object allows specification of the regression model. The NumTerms property defines the number of coefficients to be used by a regression, and is relevant only for regressions with variable number of terms (polynomial and Fourier).

For a polynomial regression, the number of terms is one more than the order of the resulting polynomial. The maximum number of terms for a polynomial is the number of data points, and the minimum number of terms is two (linear).

The following image illustrates a Linear Regression since its number of terms is two:

The following image illustrates a Polynomial regression since its number of terms is more than two.

UseYIntercept property controls whether the first term of polynomial regression is fixed, when UseYIntercept is True the trend line intercepts the line x=0 at y-coordinate that is defined by Yintercept property.

The following image illustrates a non-fixed Linear Regression since the UseYIntercept property is False.

The following image illustrates a fixed Linear Regression since the trendline is set to intercept the line x=0 at y-coordinate that is defined by the RegressionOptions.Yintercept property: