Question

It is estimated that the average number of events during a year is three. What is the probability of occurrence of not more than two events over a two-year duration? Assume that the number of evets follow a poisson distribution.

• A. 0.052
• B. 0.062
• C. 0.072
• D. 0.082

Answer 1

The correct option is B 0.062

X = {Number of events in 2 year duration}
$Avg.\left(\lambda \right)=3$ per year ( 6 / 2 year)

where $\lambda =$ Av. Number of events

So $P(x\le 2)=P(x=0)+P(x=1)+P(x=2)$

$=e^{-\lambda }[\frac{{\lambda }^0}{0}+\frac{{\lambda }^1}{1}+\frac{{\lambda }^2}{2}]=0.0619$