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Old 10-20-09, 02:08 PM   #1
jpete1966
 
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Default What's the % on this?

If I were to flip a coin 73 times what % of the time will it come up 18 times one way and 55 times another?

Last edited by jpete1966; 10-20-09 at 04:19 PM.
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Old 10-20-09, 04:45 PM   #2
u21c3f6
 
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1.16449E-05

Assuming the coin is 50-50, the answer is for 18 heads or 18 tails. For just one specific way, 5.82247E-06

Why?

Joe.
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Old 10-20-09, 05:56 PM   #3
LT Profits
 
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The OP said in another thread that he is 18-55 in his last 73 plays. That sounds like my baseball record.
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Old 10-20-09, 06:23 PM   #4
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So is that 1.16% that it hits exactly 18? What would the % be for up to 18 out of 73?
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Old 10-20-09, 06:38 PM   #5
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i asked this question elsewhere the other day. and someone suggested the following.

google binomial distribution calculator. the first one listed worked for me
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Old 10-21-09, 09:19 AM   #6
u21c3f6
 
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Quote:
Originally Posted by jpete1966 View Post
So is that 1.16% that it hits exactly 18? What would the % be for up to 18 out of 73?
For exactly 18 wins it would be: 0.000582247%

For 0 to 18 wins it would be: 0.000845681%

In other words, something that really shouldn't happen if one is truly wagering on 50-50 events. On the other hand you may have truly found an awesome edge! It's just the opposite of what you think.

http://stattrek.com/Tables/Binomial.aspx

Joe.
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