“It all averages out” is one of the most nebulous phrases that I know. On the surface, it sounds fine, but if you take a deeper look, you begin to see that’s there’s more to things than just the “average.” Take my neighbor situation, for example. I live in a townhouse which sits between two others (out of a block of five). On my left, one of my neighbors practices on his piano sometimes. I’m not infrequently greeted with soft, dulcet tones as he practices. I’ll grant that there are times when I can hear his TV through the wall, but that’s generally the bass portion of things and this is infrequent. The house to my right is a different story. It’s inhabited by a shouty drunk man. This guy frequently blares his stereo, loudly scolds his cat, and converses loudly and/or argues with a parade of low-level low-lifers and the occasional paramour. For example, I was treated to an overheated argument that centered around a lady friend of his not being able to float him $500 right away last Saturday evening. This eventually ended after what sounded like three iterations of the argument. Three loud iterations. The next night a man came by to tell him not to touch his sister while yelling into his house while ol’ Shouty McDrinkPants yelled back out a window. Good times.
Thus, if you “average” these two neighbors out, you get something approaching calm. But the reality is that I have to deal with wild swings in my auditory intake. It “averages out” but that’s not the issue. The issue is one of variance. I’d happily trade silence on my left side for a corresponding cessation of drunken yammering on my right. That sort “averaging out” would result in the general level of quiet being more consistent. I’d happily trade pleasant piano music for a lot more quiet from a late-stage alcoholic. In short, you can’t just look at the mean, but the variance as well. Thus endeth the lesson.