More Probability !!

[MadHatter]

Seeing as we have finally fought some ignorance in a different probabilty thread, I think it's time for another one.

Assume someone takes a coin and tosses it in to the air 100 times. Also assume that the chances of a head or a tail coming up are exactly 50/50.

What are the odds that after 100 tosses of the coin, the result will be 50 heads and 50 tails?

[Cabbage]

The probability that the first fifty tosses are heads and the last fifty tosses are tails is pretty clearly (1/2)100.

Then there's C(100,50) (binomial coefficient) different ways to pick which 50 of the 100 tosses are going to be heads, so the probability there's exactly 50 heads is

C(100,50) * (1/2)100, which is about 7.9589%.

[MadHatter]

Originally posted by Cabbage
The probability that the first fifty tosses are heads and the last fifty tosses are tails is pretty clearly (1/2)100.

Then there's C(100,50) (binomial coefficient) different ways to pick which 50 of the 100 tosses are going to be heads, so the probability there's exactly 50 heads is

C(100,50) * (1/2)100, which is about 7.9589%.

BZZZZZZZZZ!!!

Wrong Answer !!!

[MadHatter]

The answer I get is about 1 in 12.7

I misread your answer. I think 8% is about 1 in 12.7...