Subject: A Simple Math Lesson -Pegasus

Hi.  I'm here to reply to a remark made by one of the reviewers when they 
reviewed Second Coin Toss.  It only allows you to negate ONE flip, so you 
would not redo Barrel Dragon's three flips, just one of them.  The 
probability of Barrel Dragon's effect going off becomes LOWER than 
75%.  I'm here to work out the exact probability.

These are the eight possibilities:

HHH

HHT

HTT

HTH

TTT

TTH

THH

THT

As you can see, out of these, HHH, HHT, HTH, and THH give you Barrel 
Dragon's effect.  So, normally, its probability is 1/2.  What if you have 
Second Coin Toss on the field and you flip one of the probabilities that 
DON'T get you Barrel Dragon's effect?  Let's figure it out:

HHH

HHT

HTT -> 1/2 chance of changing one of the tails to a heads (out of 1/8, so 
it'd be 1/16)

HTH

TTT -> 0 chance

TTH -> 1/2 chance of changing one of the tails to a heads (same)

THH

THT -> 1/2 chance of changing one of the tails to a heads (same)

Let's sum up the probabilities:  1/2 + 1/16 + 1/16 + 1/16 = 11/16.  That's 
right.  11/16 (for comparison, 75% is 12/16).

Wow, this is like when one of the guys who reviewed Barrel Dragon said the 
probability was 2/3 instead of 1/2... overshot again.  (The key lies in the 
fact that you can only redo ONE flip, so with TTT you cannot do anything 
about it)


Questions, Comments, Math Mistakes (gasp, I hope I didn't make one...)

<mailto:qc@fengyuan.com>qc@fengyuan.com


-Pegasus

(If you don't understand, don't worry.  90% of my math class doesn't 
understand probability, and they're the ones who are supposed to be "gifted.")