The large barrel on the input Axon is a probe that collects data. Since the barrel is placed on the activity point, it is storing the 12 data samples that are injected into the network. This is exactly what gets displayed in the x axis of the ScatterPlot. We have found a way to compute the regression line equation, but we still do not have a measure of how successfully the regression line represents the relationship between x and d . For instance, by simply scaling the data, you can change the MSE without changing how well the data is fit by the regression line.
Intermediate values describe partial correlations.
The method of least squares is very powerful. It can be generalized to higher order polynomial curves such as quadratics, cubics, etc. In this case nonlinear regression models are obtained. More coefficients need to be computed but the methodology still applies. This case will be pursued later in this chapter.