November 25, 2004 (Ira Pilgrim)
I'm smarter than the average bear.
Yogi Bear
I can't think of a more worthless number than the average(either the mean or the median). Yet, the average is used more than any other value, probably because it is easy. It is a value that can be expressed as a single number. The average temperature, rainfall, intelligence, height, weight, and so forth. It may not tell you absolutely nothing of real value, but it is close to nothing.
The cities of Mythical and Fictional both have an average temperature of 70 degrees Fahrenheit. Sounds pretty good, eh? You would expect those two cities to have similar climates. However Mythical has a year-round temperature ranging from 60 to 80 F. degrees, while Fictional has temperatures that ranges from minus 20 to 130 degrees. Their average rainfall is also similar, but Mythical has an inch or two of rain every couple of weeks, while Fictional has zero rainfall for 9 months of the year, and a deluge for 3 months, which includes frequent flooding. It is comfortable in Mythical for almost all of the year, while Fictional can be miserable most of the time.
The same thing applies to average intelligence. In any way that you measure it, below average includes people who can hold down a reasonable paying job, to bed-ridden people who can't function at all, while above average can range from dull to genius. Albert Einstein and George W. Bush are above average in intelligence. So what? Aside from both of these men being above average in intelligence, there is no resemblance whatever between them.
I have been measuring rainfall at my home for over 20 years. I graph it as cumulative rainfall against time in months. Occasionally someone asks me if this year was above or below average. I tell them that I don't know. I don't say what I am thinking, which is that I not only don't know, but I don't care. Average rainfall has no meaning for me. What matters to me is whether there is enough water to fill my 40,000 gallon cistern before the rainfall stops for the summer. I don't care how much snow fell in the Sierras or whether a reservoir has filled to capacity. Those things are important to city dwellers and the people who use or provide that water. Even to them, the average tells them very little. The city of San Francisco gets most of its water from a reservoir in the Sierra Nevada mountains. Summers in California are usually rain free and almost all of the rain falls during the winter months. It falls as snow in the Sierras and the snow pack is an important source of stored water. Dealing with the San Francisco water supply is an intricate proposition, but whether the rainfall is above or below average for the year doesn't count for much. Its main value is that it allows the people who broadcast the television news to say, "This has been an above average year for rainfall."
I am at about the average height for males in my generation. However, I prefer to think of myself as the either the tallest midget or the shortest giant in the world.