How high is eye level?
It turns out, a patron, who was definitely on the short side, wanted to hang a piece of art. However, knowing that her "eye level" was below average, she wanted to know if there was some "golden mean" eye level that would put the art at a pleasing height, no matter how tall the viewer was.
I wasn't entirely sure how to approach this one. Actually, my first thought was to check the Statistical Abstract of the United States just to see if it would give the average height of the citizenry, but I didn't think it gave physical statistics (I checked anyway, and no, it doesn't).
I figured an open web search for phrases like "how high is eye level" would produce all sorts of opinions, and it did. Then we tried a few searches specifically for "how to hang artwork" and found a few other opinions.
The patron seemed uncomfortable with the range of answers - they were all close, but not precise. It seemed like she wanted a single answer, and a reason why that was the answer.
So, we decided to go back to the "average height of a person" approach. A search for average height of a person lead to a Wikipedia article for human height. The section on US citizens cited a Centers for Disease Control report [pdf], which gave me the idea to see if the data was on their website.
Now it was just some quick math:
|Average height of women older than 20:||63.8 inches|
|Average height of men older than 20:||69.4 inches|
|Sum of the averages:||133.2 inches|
|Sum divided by 2 to get average average:||66.6 inches*|
|Average minus 3.5 inches (to get from top of the head down to eye level):||63.1 inches, or 5' 3.1", or 5' 3-1/8"**|
So based on the data and our math, average eye level for Americans over 20 is 63.1 inches. She seemed very pleased with this answer - it seemed to me just as arbitrary as the rest we found, but at least our arbitrary figure was backed up by research and math. Regardless, I think that was exactly what she wanted, and she thanked me and left.
This was fun, and I can't help but think she will repeatedly recount this story any time someone comments on the artwork in her house.
*The average person is Satan!
**This was converted using Wolfram|Alpha and the Excel formula =INT(A1) & " ft " & TEXT(MOD(A1,1)*12, "# ??/16 ""in"""). I did this on my own after the fact - the patron though was happy with "5 foot 3 inches, and a little more," to account for the .1 - besides, the 3.5 inches down to eye level was a rough estimation anyway.