Degrees of Freedom

It sounds like some kind of Ph.D. program for ‘Muricans, but it’s actually a very subtle statistical concept related to how many different ways a system can vary. You’ll need to know the number of degrees of freedom in a scenario anytime you calculate a Chi-Square statistic, and you’re already automatically using the number of degrees of freedom in every standard deviation calculation. (Pssssssssst. It’s the n minus 1 on the bottom of the standard deviation formula.)

Let’s say you just “bought” 12 different candy bars from the vending machine, and by “bought” we mean “slammed into the machine until it spewed its candy goodness everywhere.” You plan to binge them all in one sitting. This “system,” and by “system” we mean your gluttonous feast, has eleven degrees of freedom. For the first eleven choices of which candy to inhale, you have multiple options at each stage, but for the twelfth choice, you are forced into that last remaining bar. There was no freedom to vary the last choice. Once you ate the other eleven, you had no other choice. Eleven of your choices were “free,” while the twelfth was forced on you...hence eleven degrees of freedom.

Oh, and those wrappers aren’t cleaning up after themselves, champ.