Visualisation of Lines of Best Fit

Humans possess a remarkable ability to recognise both simple patterns such as shapes and handwriting and very complex patterns such as faces and landscapes. To investigate one small aspect of human pattern recognition, in this study participants position lines of "best fit" to two-dimensional scatter plots of data. The study investigates the variation in participants' fits and whether there is some consistent metric being used in fitting the lines. For example, is there a natural tendency toward fitting lines similarly to one of the standard regression lines: vertical, horizontal, or orthogonal. This study also investigates the effect of outliers on the line a participant fits to a scatter plot with a strong linear trend and provides guidance for future inquiries. Finally, this investigation considers some practical aspects for classroom teachers.