In Algebra, I gave students the option of using Desmos or a graphing calculator to find lines of best fit. I went over examples of both then dove into Dan’s Grocery Line activity.

I started by asking students which line they would pick, a little over half in each period said the left. I gave them about half of the data Dan provided (I did this last year also and there were some issues with data overload, but that was by hand) and let them loose.

Something interesting happened.

Most of my students set their cellphones aside and used graphing calculators. I am not sure why (I will report back tomorrow). My prediction is we have had quite a bit of practice creating scatter plots on them and students are more comfortable with calculators.

We talked about what the slope, intercept, and r-value meant, and also possible reasons why data is so inconsistent. They were hooked on this after this picture!