A *correlation* is exactly what it sounds like: a *co-relation, *or relationship — like the *correlation* between early birds waking up and the sun rising. But *corollary *is more like a consequence, like the *corollary *of the rooster crowing because you smacked it in the beak. Both words love the math lab but can hang with the rest of us, too.

A *correlation* is a relationship, but not a cause and effect one*.* In statistics, a *correlation* is some connection between random variables or data values. Since *correlation *is a kind of relation, it's often followed by "between." Here are some examples of *correlations *out in the world:

Correlationis not necessarily causation, so I'm sure this has nothing to do with the departure of Rahm Emanuel. (New York Times)Their study looked only at wider geographical patterns, showing a

correlationbetween an area's radon levels and rates of the skin cancer. (Reuters)

*Corollary,* on the other hand, is one thing naturally following another. In mathematics, a theorem is a statement proven true through reasoning. Its *corollary* is a statement so closely related that it doesn't need to be proven independently. For the rest of us, it's more like the aftermath of something. Let's look at some examples:

The

corollaryto this finding is that dairy products have no effect on cough, he said. (New York Times)There is a natural foreign policy

corollary: those who see America as a work in progress are less likely to view it as exceptional. (Time)

How can non-math geniuses keep the two straight? Remember that *cor relation* has an equal, though not necessarily defined,

**ship.**

*relation**Corollary*is more like a

*consequence*.