Thursday, September 16, 2010
Wednesday Math (one day late), Vol. 127: A nice website with a small problem
Okay, there's this website called Maps 'n' Stats, a great source of demographic info for the 50 states and D.C. I particularly like how fine a demographic split they have, so you can see in what states they are breeding like rabbits and in what states they are dying like flies.
For example. Utah. Both Rabbits and Flies. Lots of babies, not so many old people.
So far, so good.
But if we add up all the percentages for Utah's demographics we get 99.2%. In California, the numbers are different, but the sum is also 99.2%. In Texas, the sum is 99.3%.
The website is nice enough to give us the raw numbers, so I plugged the Utah numbers into my spreadsheet to find out why the totals were so far off from 100% and consistently low.
It appears that the nice folks who run maps-n-stats.com never learned about rounding up. All the numbers are simply truncated, so 9.38% is written as 9.3% instead of 9.4%.
As a grateful educator, I hope the folks from that website fix this bug in the near future. It's so easy to get this right.