# Lesson 5

Watch Your Calculations

These materials, when encountered before Algebra 1, Unit 1, Lesson 5 support success in that lesson.

### Lesson Narrative

The mathematical purpose of this lesson is for students to recall how to calculate measures of centers and variability from their work in middle grades, including mean, median, mean absolute deviation (MAD), and interquartile range (IQR). In the associated optional Algebra lesson, students are given the opportunity to recall how to calculate the interquartile range and mean absolute deviation. This lesson connects to upcoming work, because students will interpret data using measures of center and measures of variability throughout the unit, so it is important they understand what these statistics mean. This lesson also helps students to compare and contrast data sets using measures of center and measures of variability in a future lesson. Students engage in MP3 as they discuss their work with partners during the row game.

### Learning Goals

Teacher Facing

- Calculate measures of center (mean and median) and measures of variability (MAD and IQR).
- Understand the difference between measures of center and measures of variability.

### Student Facing

- Let’s calculate mean, median, mean absolute deviation (MAD), and interquartile range.