So let us look at the bit of the context and a bot of the mathematics;
A bit of history: Ferrari has traditionally been very strong in Brazil, and off course Massa knows the track inside out. It is not unreasonable to expect a Ferrari 1-2 in Brazil with Alonso being the winner (Ferrari is very strict at implementing team orders
). At the same time, RBR definitely has the pace to come 1-2 in qualifying and defend their positions in the race.
Context: Alonso is ahead in the championship and is good at handling championship pressure, a field in which Hamilton is weak, and Vettel and Webber are unknowns. Ferrari and RBR have matching pace with Mclarens struggling a bit in that department.
Mathematics: I see two scenarios emerging with almost equal likelihood, with a very small likelihood of anything else happening.
Scenario 1 - 40% Likelihood: Alonso 1, Massa 2: If this is the case, only Webber will be left with a chance to catch Alonso, and that too only if he stays in the top 5. Even if he comes in top 5, he will have to expect a very poor showing from Alonso in Abu Dhabi. So, if Alonso wins, RBR is sure to give team orders in favor of Webber, and Webber at No. 3 (a 40% chance) will be left 21 points behind Alonso, and he can win if he wins the race (40% chance) and Alonso stays outside top 8, which I don't see happening barring an Engine blowout incident (which is again quite likely, say 30% in Abu Dhabi). Combined together that means a 5% chance for Webber to win the race. In this case, any other driver will have no chance of overtaking Alonso.
Scenario 2 - 40% likelihood: Vettel 1, Webber 2, Alonso 3, Massa 4: Alonso at 246, Webber at 238, and Vettel at 231, will be the final standings. I think RBR will likely not implement team order in this case, as Vettel will have a good chance of winning the title, and Webber can still win it if he seals the No. 1 in Abu Dhabi with Alonso staying at No. 3 or lower. So, they will wait till Abu Dhabi to see whether to implement the team orders or not. However, if this happens, chances of Alonso winning the title will be very slim as his Engine is in pretty bad shape, say 20%.
Scenario 3 - Hamilton 1, ____ A 50:50 chance in favor of Hamilton, or in favor of Webber or Alonso.
Net-Net, the likelihhods are as follows:
1. Alonso: 50%
2. Webber: 25%
3. Vettel: 15%
4. Hamilton: 10%
And if Alonso wins in Brazil, the title race will be more or less settled.
maybe i'll get someone to push the 'submit' button for me 
