MathBench > Statistical Tests

Goodness of Fit Tests

The day is saved … or not

Apparently we have saved the day. 40% of sickdays SHOULD fall on Monday or Friday, which means that employees are not abusing the system.

dilbert cartoon

But wait. What if next year, Evil Pointy-Haired Boss (EPHB) finds that 42% sickdays fell on Monday or Friday??? Proof positive, in his view, that employees are out to get him.

Let's be Dilbert for a minute. How could we confirm or disprove Evil Pointy-Haired Boss (EPHB's) claim? Clearly 42% is more than 40% -- but how much is too much? Do the extra 2% just represent the natural "slop" around 40%?

In fact there are (at least) two ways to do this:

icon 1. The Brute Force method: make up ("simulate") lots of data. This is conceptually not too hard, but it requires a lot of computation.

icon 2. The Statistical method: chi-square test. This is conceptually harder, but requires only basic arithmetic, a calculator, and a lookup table to implement.

We'll try them both, and you can see which one you like better.