If you stop at this point and predict that the differenced series is constant, you have merely fitted a random walk or random trend model.
Note that, except for the gratuitious constant term, model A is the seasonal random trend (SRT) model, whereas model B is just the seasonal random walk (SRW) model.
A model with two orders of total differencing assumes that the original series has a time-varying trend (e.g. a random trend or LES-type model).
Notice that this is just the seasonal random trend model fancied-up by adding multiples of the errors at lags 1, 12, and 13.
These are, of course, the residuals from the seasonal random trend model that we fitted to the auto sales data earlier.
As shown, in low dimension, Halton sequence has suitable dispersion, but by increasing the dimension, convergence is revealed as in high dimensions, its random trend is lost and hypercube is not covered uniformly.
The distribution pattern of the molar ratio of Na/Cl versus electrical conductivity displays a random trend meaning lack of evaporation effect on chemistry of groundwater in Dammam aquifer.
Having not watched all of them, most are still assuredly terrible in that way jokes that fully rely on a "trending topic plus other random trending topic" construction tend to be.
