1. ## Coin Flip

A coin is flipped "n" times. What is the probability that exactly"h" heads emerge? Explain.

- I just want to make sure that I'm doing this right.

I have the sample space as 2*n and the P(s)= H/(2*n).

Is this correct??

2. Originally Posted by ccdelia7
A coin is flipped "n" times. What is the probability that exactly"h" heads emerge? Explain.

- I just want to make sure that I'm doing this right.

I have the sample space as 2*n and the P(s)= H/(2*n).

Is this correct??
No...

When you flip the coin 'n' times, the head 'h' can appear in $\displaystyle {n \choose h}$ ways.

So P(exactly 'h' heads) = $\displaystyle \frac{{n \choose h}}{2^n}$

3. Originally Posted by ccdelia7
A coin is flipped "n" times. What is the probability that exactly"h" heads emerge? Explain.

- I just want to make sure that I'm doing this right.

I have the sample space as 2*n and the P(s)= H/(2*n).

Is this correct??
The probability of any particular distribution of n coin flips with order taken into account is $\displaystyle \frac{1}{2^n}$. So in order to determine the number of coin flips with exactly n coming up heads the formula is $\displaystyle {_8}C{_n}\cdot{\frac{1}{2^n}}$.