The easy way to calc probabilities for your deck designs

[GuestOfHonor]

When building decks and evaluating how consistently they'll play, many people struggle with how to calculate the probability of:

1. Getting at least one specific card A by the turn they need it to appear, while balancing that probability against having too many of that card when they don't want it to appear.
2. Getting a combo of card A AND card B, either by the same turn or card A on turn X and card B on turn Y.
3. Getting EITHER card A OR card B by a specific turn.
4. Extrapolating from specific cards to general events, the odds of both event A AND event B happening, or of EITHER event A OR event B happening.

Unfortunately, shannong appears to be as much a victim as anyone in this struggle. Most of the OP is just plain wrong, and with over 10,000 views there still hasn't been much correction. Why has this been stickied?

[Gondorian]

Unfortunately, shannong appears to be as much a victim as anyone in this struggle. Most of the OP is just plain wrong, and with over 10,000 views there still hasn't been much correction. Why has this been stickied?

A better question would be "Why hasn't this been unstickied?"

I have addressed that now.

[GuestOfHonor]

A better question would be "Why hasn't this been unstickied?"

I have addressed that now.

Fair enough! I may give explaining this probability stuff a go myself.

[Pat Jay]

I don't think this is correct. The standard formula is: P(x OR y) = P(x) + P(y) - P(x AND y), which in case of independent events x and y reduces to P(x) + P(y) - P(x)P(y).

Just taking the average of the probabilities can never work, not even as approximation, as P(x OR y) should always be larger than both P(x) and P(y)

Yes I also think this is the case. Because I was confused by this and so I asked this question in yahoo answers

http://au.answers.yahoo.com/question...9013107AAtdvgS

[Blackstronaut Moondick]

How would you calculate the probability of a draw when that draw’s probability is contingent on another previous draw? Fox example:

Aramia and 56 cards in deck
4x Bad Santa
4x Loom of Fate
4x Isadora

Should be roughly ~75% to draw Loom or Santa by turn 2
I use Loom/Santa to provide three cards by turn 5
Aramia also draws a card on turn 4/5
By turn 5 this gives a sample size of 14/15 depending on start position

This means if I successfully draw Loom/Santa on turn 2 I then have ~75% to draw Isadora on turn 5. However what I really need to know is what is the overall probability of drawing Isadora by turn 5 that accounts for the possibility of missing the other draw. Is it as simple as figuring 75% of 75% or is there something else? Also how do I do that lol. Ty!

[PAulAblGOe]

Yes, It was just a bit of fun really, and one of my initial ways of trying to add value here. Now I have the articles, deckbuilder, leagues, tournaments, so I don't really promote the simulator any more.