Answer :
The incorrect statement is C. μ = 4 because the service rate (μ) is actually 15 calls per hour, not 4. The other statements about the suitability of the M/M/s and M/M/1 models and the arrival rate λ being 14 are correct.
We are asked to identify which statement is not true given the following information about call arrivals and processing rates:
Calls arrive at a rate of 14 per hour (λ = 14).
The sales rep processes calls at an average rate of 4 minutes per call.
Since there are 60 minutes in an hour, the service rate is μ = 60 / 4 = 15 calls per hour.
The call arrival rate λ is indeed 14.
The service rate μ is calculated as 15 calls per hour, which is correct given the average processing time of 4 minutes per call (60/4).
The incorrect statement is:
C. μ = 4 - This is false because μ is the average service rate, which is 15 calls per hour as we calculated above, not 4.
Regarding the queuing models:
An M/M/s model is suitable to analyze this problem where 's' represents the number of service channels (in this case, it is '1'). An M/M/1 model should be appropriate since the system has a single service channel (the sales rep), and the call arrivals and service times both follow an exponential distribution.
