# Thread: probability of the bird's egg hatches

1. ## probability of the bird's egg hatches

i have solved the first part. but i am having problem with the 2nd part. how to do ' find the probability that seven or more eggs hatched in a year? '

2. ## Re: probability of the bird's egg hatches

I think you want to just create a new random variable, also with a binomial distribution, but now the underlying $p$ is given by the probability of hatching, i.e.

$p=Pr[\mbox{egg produced}]Pr[\mbox{egg hatches}]=\left(\dfrac 3 4\right)\left(\dfrac 7 {10}\right)=\dfrac{21}{40}$

As before $n=8$

Now just evaluate the CDF of this new binomial distribution at $k=6$ and the probability you want will be 1 minus this value.