A single-server waiting system is subject to a homogeneous Poisson input with intensity
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If there are not more than 3 customers in the system, the service times have an exponential distribution with mean 1/μ = 2 min] If there are more than 3 customers in the system, the service times are exponential with mean 1/μ = 1 [min]. All arrival and service times are independent.
(1) Show that there exists a stationary state distribution and determine it.
(2) Determine the mean length of the waiting queue in the steady state