elementary statistics

Question

The random variable xx represents the number of received at a help desk in one hour, and it has a Poisson distribution with a mean of 15.6.

What is the variance?

variance = 

What is the standard deviation?

standard deviation = 

Answer 1

Let λ = 15.6 received in one hour, where X ~ Poisson (λ). λ is also a mean (average).

The mean is the same as the variance according to the textbook such as μ = σ². The standard deviation is the square root of the variance such as σ = √σ².

Variance: σ² = 15.6

Standard Deviation: σ = √15.6 ≈ 3.95