# Probability question Help!

1. Apr 28, 2005

### tae3001

A coin is tossed 4 times. What is the probability of getting more heads than tails?

2. Apr 28, 2005

### juvenal

Use the binomial distribution.

3. Apr 28, 2005

### JamesU

4. Apr 28, 2005

### Zaare

Juvenal's suggestion is good, but I thought I'd give you an alternate way of solving the problem. What is the probability of a certain combination och heads and tails? For example: first throw you ger tail, the three following throws heads come up. Then, think about in how many such combinations you would get more heads than tails.

5. Apr 28, 2005

### tae3001

is there.. a formula for it..
if its tossed 4 times.. and there are 2 sides..
wouldn't it be 4 choose 2???
if there are more H that t woudl it be HHH and T...
i hate probability questions..

6. Apr 28, 2005

### juvenal

7. Apr 28, 2005

### Zaare

Every time you throw there is 50% chance of T and 50% of H.
So, if you throw once you have (P(x)=probability that x happens):
1. P(H)=1/2
2. P(T)=1/2.
If you thow twice:
1. P(H,H)=(1/2)*(1/2)=1/4
2. P(H,T)=(1/2)*(1/2)=1/4
3. P(T,H)=(1/2)*(1/2)=1/4
4. P(T,T)=(1/2)*(1/2)=1/4
If you throw four times there is 1/16 chance you'll get one of the 16 combination:
1. HHHH, 2. HHHT, 3. HHTH,... etc.
These three examples are all more Heads than Tails, how many more such combinations are there? If you can answer that, you're done.

8. Apr 28, 2005

### tae3001

I get it.. thanx.. u guys helped me graduate..(LOL).. awesome..