The Event Attendance Status viewport shows a graph of the event attendance responses collected by your agents. The options are: Can't Go, Going, Maybe, No Response (meaning the agent wasn't able to reach the prospect), and N/A (meaning no status has been reported yet).
The viewport can be viewed either as a chart or a table. You have the option to switch between the two, as well as export the totals from the viewport, by clicking on the gear icon on the top right of the viewport.
You also can click on any particular category to see the list of prospects who provided that response to their agent.