# Statistics, probability help please !

1. Jul 6, 2011

### Calculator14

1. The problem statement, all variables and given/known data

In a certain high-risk group, the chance of a person having suffered a heart attack is 70%. If four persons are chosen from the group, find the probability that at least one will have had a heart attack.

2. Relevant equations

(work shown below) these would be dependent

3. The attempt at a solution

(.7)/(4) = 2.8

2. Jul 6, 2011

### daveb

It might be easier to think of the chance that a specific individual doesn't have a heart attack, so what are the chances that none of the individuals have heart attacks (and you might want to rethink the dependence).

3. Jul 6, 2011

### the_amateur

i don think it is a dependent event

the probability of a person with heart attack is 0.7

so the probability that among 4 at least 1 has heart attack = 1 - probability that none have

= 1 - (0.3)$^{4}$

must be correct but verify it

4. Jul 6, 2011

### Laiva-59

Your attempt doesn't make any sense.
Remember: probability can never be more than 1.

So if you find 2.8, think again.