That’s a statistics question, not a telephony one, although, as members is a synonym for agents, it doesn’t make sense unless you replace member by caller.
To a first approximation, it will be an average of 25ms, from when the agent is hungup, before the next call to the agent is imitated, assuming the calls arrived at random times within their nominal second of arrival. However, in exceptional cases, it could be up to 1000ms.
If you use AgentLogin type agents, the beep will take another 400ms. For other agent arrangements the specifics of setting up a call to the agent will affect the exact latency.~
(This may be one of those tricky statistics problems where the answer is not as intuitive as it seems. I’ve assumed that the calls are equally spaced within the second, and therefore the average delay is half that interval, but, if truly random, they won’t be equally spaced. With one caller in the queue, the statistics are straightforward, and the answer would be 500ms, from hangup to start of new call.)