After teaching my students about scatterplots, correlation, and the line of best fit, I take a day for them to do a hands-on lab, in which they measure their height (in inches) and their forearm length (from the tip of their elbow, to the bony point on their wrist), and we plot the class data, write the equation of the line of best fit, and then use the equation generated both forwards and backwards. They will need 45 minutes to an hour to do this in class.
Some years, the data have very little correlation, so I have the students include a point for "microscopic man" at (0, 0). One of the most challenging aspects of this activity is that students base their calculation of the slope on the squares on the page, instead of taking into account that each vertical unit counts for a different amount from each horizontal unit.
The preview file is a pdf so you may see exactly what's included; the product file is a word document, which you may want to edit for your students. (For instance, I have my name, Mr. Jonnard, on it, and you may wish to change it to a more familiar person).
Immediately before this worksheet, I use the worksheet named 'Direct Variation Functions Fall 2013' (http://www.teacherspayteachers.com/Product/Direct-Variation-Functions-Fall-2013-1106044
), and immediately after this worksheet, I use the resource named 'Final Exam Study Guide Accelerated Algebra 1 Fall 2013' (http://www.teacherspayteachers.com/Product/Final-Exam-Study-Guide-Accelerated-Algebra-1-Fall-2013-1106636
Keywords: scatterplot, line of best fit, forearms, height, lab, Jonnard