What's the % on this?

[jpete1966]

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?

[u21c3f6]

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.

[LT Profits]

The OP said in another thread that he is 18-55 in his last 73 plays. That sounds like my baseball record.

[jpete1966]

So is that 1.16% that it hits exactly 18? What would the % be for up to 18 out of 73?

[polson22]

i asked this question elsewhere the other day. and someone suggested the following.

google binomial distribution calculator. the first one listed worked for me

[u21c3f6]

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.