Stats -- Watch Your Math

One of you wrote that from 1984 to 2001, there was a 48.1 percent increase in the number of households with computers. I assume you deduced that by looking at 2001's 56.3 percent and taking away 1984's 8.2 percent. The difference is 48.1 percent.

But here's the problem: what you said was that latter number represented the increase in the number of households with computers. In that case, the actual increase is 586 percent.

How did I get that? Again, you said it was the number of households. If 8.2 percent of households have computers and that number doubles, it goes to 16.4 percent. And that increase is 100 percent, since 200 percent of 8.2 equals 16.4, right?

What you meant to say was that there was a 48.1 percent increase in the percentage of households with Internet service. But that's not what you said. And yes, unfortunately that is a fatal.

Math can be tricky, I know. Most journalists get into writing because we can't stand math. And I'm not suggesting you avoid using math in your reporting; math is amazingly helpful in letting readers understand a story. But be sure you understand the math you're using.

If you need help, there are endless math resources -- percentage calculators and such -- online. Just Google away for some help.