This is the average of the broadcast-packet delta values sampled over the object's configured collection intervals. The average smooths out single-cycle noise, so an admin trusts this value more than a single delta reading when deciding whether broadcast traffic on this interface has a genuinely elevated baseline versus one brief blip. A deltaAvg that has crept up over several days even though any single delta spike looks tolerable would indicate a slow, sustained increase in broadcast chatter on this port worth investigating before it becomes a storm.