# expected value - probability

• Oct 4th 2007, 07:01 AM
inneedofhelp
expected value - probability
You are visiting the rainforest, but unfortunately your insect repellent has run out. As a result, at each second, a mosquito lands on your neck with probability 0.5. If a mosquito lands, it will bite you with probability 0.2, and it will never bother you with probability 0.8, independently of other mosquitoes. What is the expected time between successive bites?
• Oct 4th 2007, 07:53 AM
CaptainBlack
Quote:

Originally Posted by inneedofhelp
You are visiting the rainforest, but unfortunately your insect repellent has run out. As a result, at each second, a mosquito lands on your neck with probability 0.5. If a mosquito lands, it will bite you with probability 0.2, and it will never bother you with probability 0.8, independently of other mosquitoes. What is the expected time between successive bites?

In 1000s 500 mosquitoes land on you and of those 100 bite you, so in 1000
seconds you are bitten on avaerge 100 times ...

RonL
• Oct 4th 2007, 08:16 AM
inneedofhelp
Quote:

Originally Posted by CaptainBlack
In 1000s 500 mosquitoes land on you and of those 100 bite you, so in 1000
seconds you are bitten on avaerge 100 times ...

RonL

I'm not sure if that answers the question...

What is the expected time between successive bites?
• Oct 4th 2007, 11:14 AM
CaptainBlack
Quote:

Originally Posted by inneedofhelp
I'm not sure if that answers the question...

What is the expected time between successive bites?

... ellipsis means you should be able to complete the solution from this point.

RonL