The mathematical purpose of this lesson is for students to understand that measures of center can be more or less representative of a data set depending on the data distribution shape. Previously, students learned names used to describe typical shapes of data distributions and how to interpret data by using the shape. Students have also learned how to find the mean and median and use them to represent typical values in a data set. In the associated Algebra 1 lesson, students will explore the effect of extreme values on these two measures of center. This lesson will continue to build on the understanding that the median is the preferred measure of center for skewed data for upcoming lessons. 

The estimation Warm-up gives students the opportunity to make sense of problems (MP1), critique the reasoning of others (MP3), and model with mathematics (MP4). Students reason abstractly and quantitatively (MP2) when they make a connection between balance point and mean as well as when they decide which measure of center more closely represents what is typical of a data set.