Enter a brilliant adaptation by Jonathan Claydon for the cannot-go-outside-for-5-months-because-we-live-in-the-midwest group of people. I have my adaptation of it at the bottom of this post.
Students start be measuring each member of their group (see below). This measurement is known as the group member's 'real height'.
Next, we figured out how we would go about agreeing on the actual height since I don't have the actual measurements myself. With our ceiling calculations, we decided to remove the group's height which was very different before averaging the heights.
Aside: I am horrified at the rounding in this next picture of my blackboard. I wrote the numbers students told me to write without correcting their rounding errors. In hindsight I should have forced them to be correct (or attend to precision) but we were hurrying to get done before the bell. ...Plus it makes me look like an idiot.