I'd guess this is a case where the average (especially arithmetic mean) is misleading. suppose a hypothetical fire department gets four 911 calls in a day. three are for life threatening traffic accidents, and they get a vehicle on-scene in six minutes. the last call was for a cat stuck in a tree. the cat isn't going anywhere, so they take an hour to get there. they responded pretty quickly to the most serious calls, but their average response time for the day was about 20 minutes. a single outlier for a low priority situation can severely skew the arithmetic mean.