The Best Fit Line Ruler is a stationery innovation to help you draw the line of best fit on a scatter graph. Just lay the clear ruler over your graph, once data points have been plotted, and the grid on the BFLR will help you to make sure you get as many points as possible as close as possible to the central slot. Then slide your pencil along the groove and there’s your best fit line.
I invented the BFLR whilst invigilating a biology exam where I watched a student trying to find the best fit line for a graph using a wooden ruler. Find out about the lightbulb moment when the idea came to me in this interview for the Pearson International Schools Community website