Choosing the Best Measure of Center

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.

Note:

• 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.

Notes:

• 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.  

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.