Day 26: Who Pilfered My M&Ms?

This is a perennially fun day in AP Statistics.  The problem the students are given is:

In her desk in the math department, Ms. A. keeps a large jar full of m&m’s for use in her Statistics classes. Over the past few days, several m&m’s have gone missing. Eager to catch the culprit, Ms. A notes that the only people who have access to her desk are the other math teachers at the school. Ms. A sends out an email asking whether or not her colleagues have been making unauthorized withdrawals from the jar, but no one confesses to the crime.

The next day, Ms. A catches a break–she finds a clear handprint on the cookie jar (unfortunately for our suspect, that whole “melts in your mouth, not in your hand” thing isn’t really accurate). Ms. A is calling on you, the AP Statisticians, to help identify the prime suspect in “The Case of the Missing m&m’s.”

There are 10 individuals of varying heights in the math department–we’ll also consider our principal in this investigation. To identify the prime suspect, we must determine the relationship between handspan and height.

This problem was adapted from Jason Molesky’s activity at StatMonkey.  Students collect data, create a scatterplot of the class data, determine the LSRL and use it to predict the height of the culprit based on handspan.  Lots of great discussion during the period.