Yes, I had read the wikipedia entry after I saw a reference to this measure in an ICOTS paper (which wasn’t very good, other than introducing me to the measure). I’m finding that students (and teachers) have very little understanding of what a correlation coefficient is – they just learn some rule of thumb about which values are “significant” and which ones aren’t. In fact, I’m finding that students don’t really understand what a “least squares line” is either – they don’t understand the variability piece. I’m developing a unit for 9th grade biology and want students to have strategies for looking at a graph and assessing whether there is a relationship between the two variables without having to plot a line. Even more basic, students don’t really understand that an association means “as X gets larger, Y gets larger (or smaller),” so I’ve been working on some ways to help kids read scatterplots, which are somewhat of a mystery to them. (They tend to read left to right as time, for example.) So I want some way to talk to them about how strong the relationship is without getting in to plotting a line.

That’s a long answer – and I’m not sure I’m doing a great job of communicating my reasoning. (I’m in the middle of teaching a workshop on data in Puerto Rico!). If you’d like to talk more about it, perhaps we could Zoom sometime.

Andee