Camden Depot's Division Case Study

The other day, Camden Depot’s fearless leader claimed, “we can be really optimistic and dream of a Yankees collapse, but we know those things rarely happen. (https://twitter.com/jsbearr/status/626793080264503296)” I was wondering whether this is in fact the case so I figured I would take a look at how division leaders at the end of July perform for the rest of the season.
From 1998-2014, the team leading its division at the end of July won on average 93.7 games, had nearly a 75% of winning at least 90 games, had an 84% of making it to the playoffs (via 2015 rules) and a 71.4% chance of winning its division. On first glance (and second), this does appear to indicate that it’s highly unlikely that the Yankees are going to collapse.
The problem with just using this method is that it doesn’t take into account whether a division leader is only five games over .500 or fewer (less than a 50% chance of winning their division) or if a division leader is sixteen games over .500 or more (96.6% chance of making it to the playoffs via 2015 rules). The table below shows how division leaders in this situation usually perform.

Things are looking up because the Yankees aren’t quite as good as the average division leader. This next table shows how teams have historically done when they have between a 4-8 game lead and are 10 to 15 games above .500.
Ten out of fourteen of these clubs ended up winning their division and that includes teams with only a 4 game lead. All in all, it seems reasonable to argue that the Yankees have a 70% chance of winning the division based solely on history. But a 70% chance of success means that the Yankees have a 30% chance of failure. What are the chances that the Orioles will actually end up making it to the playoffs based solely on historical