Question

. A random variable X has Poisson distribution with mean equal to 0.4. What is the
probability that the random variable is greater than zero?

Answer 1

According to the Poisson distribution, the probability of a value to take the value k:

$P(X=k)=\frac{\lambda^k}{k!}e^{-\lambda}$

We know

$E(X)=\lambda=0.4$

Then:

$P(X>0)=1-P(0)=1-e^{-0.4}\approx0.33$