An alarm company reports that the number of alarms sent to their monitoring center from customers owning their system follow a Poisson distribution with $\lambda = 4.7$ alarms per year. Identify the mean and standard deviation for this distribution.
A) mean $= 4.7$, standard Deviation $= 4.7$
B) mean $= 2.17$, standard Deviation $= 2.17$
C) mean $= 4.7$, standard Deviation $= 2.17$
D) mean $= 2.17$, standard Deviation $= 4.7$

Question

Quizplus · Accepted Answer

For a Poisson distribution, the mean is $\lambda$ and the standard deviation is $\sqrt{\lambda}$. Here, $\lambda = 4.7$, so the mean is 4.7 and the standard deviation is $\sqrt{4.7} \approx 2.17$.

An Alarm Company Reports That the Number of Alarms Sent λ=4.7\lambda = 4.7λ=4.7

An Alarm Company Reports That the Number of Alarms Sent $\lambda = 4.7$