12: How big is big?

fish taking a lure
On the form below, you can put this all together. As you fill out each column, click on the button below it
to check your numbers. BTW, this is where having a calculator will come in handy. As long as you use 2
significant digits in your calculations, the program will fill in additional digits for you.

Once again, recall that there were 42 mon/fri sickdays out of 100.

observed ("o") expected ("e") (o-e) (o-e)2 (o-e)2/e
Monday/ Friday
Total 100 100    


So now you have a number which the chi-square statistic for this test, also called the "
chi-square-calc". It’s the one that’s obnoxiously flashing at you. But
what do you DO with it? You know that a big number is bad (because it means
that the data deviate alot from the model) and a small number is good (because it means the data
doesn’t deviate). But how big is big, detour signor how small is small?

Before we answer that question, we need to take a brief detour to discuss degrees of freedom.
After that, we can finally answer the question, are Dilbert’s colleagues really out fishing on their long weekends?