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MickeyHoldem
12-12-2004, 04:04 PM
Just wondering if this formula is correct...

p = your chance of winning
T = number of trials
x = min. wins

x
---
\
/ nCr(T,i) * p^i * (1-p)^(T-i)
---
i=0

A) For a coin flip... what are the chances that heads comes up a min of 8 times out of 20... answer ~87%

B) for pocket pairs vs. 2 overs (roughly 54% - 46%)... what are the chances of losing 100 times out of 200... I calculated this as &lt;12% using the above formula

Someone claimed to have lost 156 out of 200 of these situations &lt;cough...bull&lt;cencored&gt;&gt;... somewhere around 1 in 1.97E+20

BruceZ
12-12-2004, 05:00 PM
[ QUOTE ]
Just wondering if this formula is correct...

p = your chance of winning
T = number of trials
x = min. wins

x
---
\
/ nCr(T,i) * p^i * (1-p)^(T-i)
---
i=0

A) For a coin flip... what are the chances that heads comes up a min of 8 times out of 20... answer ~87%

[/ QUOTE ]

87% is correct, but you must sum i from 8 to 20 wins, not 0 to 8.

[ QUOTE ]

B) for pocket pairs vs. 2 overs (roughly 54% - 46%)... what are the chances of losing 100 times out of 200... I calculated this as &lt;12% using the above formula

[/ QUOTE ]

You would sum i from 0 to 100 with p = 0.54 to get the probability of winning 100 or less. I get 14.3% using the equivalent Excel function
=binomdist(100,200,0.54,true).

MickeyHoldem
12-12-2004, 05:34 PM
[ QUOTE ]
=binomdist(100,200,0.54,true).

[/ QUOTE ]

WOW... excel has this built in... I'm an idiot! /images/graemlins/wink.gif