Which of the following factors is irrelevant to Little’s law?Resource input timeAverage number of customers coming in per unit of timeAverage customer flow timeNone of the above

Little's Law is a principle in queuing theory that states the average number of customers in a system (L) is equal to the average arrival rate of customers to the system (λ) multiplied by the average time a customer spends in the system (W). Mathematically, it is expressed as L = λW.

Let's analyze each of the options:

1. Resource input time: This could be interpreted as the time it takes for a resource to process a customer, which is related to the average time a customer spends in the system (W). So, it is relevant to Little’s law.

2. Average number of customers coming in per unit of time: This is the average arrival rate of customers to the system (λ), which is directly in Little's Law. So, it is relevant.

3. Average customer flow time: This is the average time a customer spends in the system (W), which is also directly in Little's Law. So, it is relevant.

4. None of the above: Since all the above factors are relevant to Little’s law, this option is incorrect.

Therefore, none of the factors listed are irrelevant to Little’s law.