Correlation: It might not imply causation but it does explain my mental state.

This is a graphThis graph shows what it’s like in my head on each weekday. Coming off a relaxing and fun weekend, I tend to be what could almost qualify as bright-eyed and bushy-tailed on Mondays. I’m not tired and my ability to function is top notch! Over the course of the week, my tiredness increases and my ability to function decreases. On Tuesday, I tend to function like an average adult more often than not. On Wednesday, I’m still hanging in there. By Thursday, I’m a little spacey, which I try to pass off as a charming byproduct of ADHD while I’m not splayed out on the couch trying to stay awake through my favorite TV show ever (The First 48. Or maybe sports. I’m too tired to be that picky.). On Friday, you might find me in my office staring vacantly out the window and composing emails that forget to contain verbs.

I believe the correlation coefficient (or the nonparametric Spearman correlation coefficient) could be expressed thusly:

-1 < r < 0

This means that one variable increases as the other decreases. It also explains why my Friday blog posts tend to be photos of my dog’s butt or completely nonsensical rambling about graphs or donut looking something or others.