Suppose that the number of accidents occurring on a highway each day is a Poisson random variable with the expected number of accidents a day equaling 3. Find the probability that 3 or more accidents occur today. Then, find the probability that 3 or more accidents occur today under the assumption that at least 1 accident occurs today.
Hi
Thanks for getting back to me.
I got this online for the pmf of a poisson.
I still don't see how you get
1- Pr(0) + Pr(1) + Pr(2)= 1-(e^-3 +3e^-3 + 9/2 e^-3)
could you provide me with the formula into which I sub the values please. I see that on the left it's each value for the probability up to and including 3 and then subtract from 1 to get probability of greater than or equal to 4, but the 9/2 on the right hand side of the equation? No idea where that came from.