Final answer:
In partial interval data collection, the behavior must occur for the duration of a time interval.
Step-by-step explanation:
In partial interval data collection, the behavior must occur for the duration of a time interval. This means that the behavior being observed needs to be present throughout the entire time interval. For example, if we are collecting data on the number of cars passing by in a 1-hour interval, the behavior of car passing needs to occur continuously during that entire hour.