Choosing the Best Measure of Center
Lesson 12 of 22
Objective: SWBAT: • Calculate the mode, mean, median, and range of a data set. • Define and identify outliers in a data set. • Determine which measure of center best represents a given situation.
See my Do Now in my Strategy folder that explains my beginning of class routines.
Often, I create do nows that have problems that connect to the task that students will be working on that day. Today I want students to analyze a circle graph in order to answer questions. Each edition of Scholastic Action typically includes a graph on its back page.
I ask for students to share their thinking. Students are engaging in MP3: Construct viable arguments and critique the reasoning of others.
I ask students to use the skills we have developed in this unit to answer the questions. Students participate in a Think Write Pair Share. I quickly review the answers to problem 1. I want to ensure that students are able to accurately calculate the mean, median, mode, and range.
- Before this lesson, I place 3 signs in 3 corners of my room that read median, mean, and mode.
I review the expectations for moving around the room. I also encourage students to go to their corner and try not to be persuaded by what other people are doing. I am interested in different ideas.
I give students a minute to talk about why they are in their corner. Then I call on students at each corner to share out their reasoning. Students are participating in MP3: Construct viable arguments and critique the reasoning of others.
We go over the notes together. I want students to understand that an outlier greatly affects the mean, since we add up all of the values and then divide by the number of values in the set. I also explain that depending on the situation, it may be better to choose a particular measure of center.
- Before this lesson, I use the exit tickets from the previous lesson to Create Homogeneous groups of 3-4 students.
- Each group also gets a Group Work Rubric.
- I create and Post a Key.
Students work in their groups while I walk around to monitor student progress and behavior. Students are engaging in MP2: Reason abstractly and quantitatively, MP3: Construct a viable argument and critique the reasoning of others, MP4: Model with mathematics and MP6: Attend to precision.
If students are struggling, I may ask them one or more of the following questions:
- How do you calculate the mode/median/mean?
- Are there any outliers? How do you know?
- For this situation, which measure of center is the best? Why?
When students finish a page, I quickly check in with them. If they are on track, I let them use the key to check their work and move on.
Closure and Ticket to Go
I ask students to turn to problem 3 about the gymnasts. I quickly go over the mean, median, and mode for each gymnast. Then as ask students to share out which gymnast they would pick to compete in the state competition. I am interested to hear why students nominated particular gymnasts. Students are engaging in MP2: Reason abstractly and quantitatively, MP3: Construct viable arguments and critique the reasoning of others, and MP4: Model with mathematics.
I pass out the Ticket to Go and the Homework.