Simulation for BTC1 bet:
EV = (83% x -BTC1) + (17% x BTC11) = +BTC1.04
Edit: calculation corrected, credit to Saint-loup
Correct, if the payout for correctly guessing the dice roll is x12 of your stake, while the odds of winning are 1 in 6, then the expected value can be calculated as follows:
EV = (1/6) * 12 - (5/6) * 1 = 1 - 5/6 = 1/6
The positive expected value suggests that over the long term, you would be expected to make a profit by taking this bet. However, in the short term, there is a high likelihood that you will lose your bet.
1 - will you take that bet?
It depends, but in general yes. It pays to place EV+ bets, despite short-term volatility.
2 - if so, what % of your available funds would you put at stake (i.e. funds you're willing to gamble and afford to lose)?
I like to be conservative. About 2% I think.