Let Your Students Decide: Mean or Median?

By: Mary Kienstra on: September 24, 2014  in: Discussion, Engagement, Kakooma, Mean, median

Some days, what you plan to teach is not what your students learn.  Friday was one of those days, but in a good way!  

Every Friday, math class begins with Kakooma Challenge.  This game has become quite a favorite.  Everyone looks forward to the challenge and hopefully beating the other classes.  (Yes, a little competition goes a long way.)  
Last week, the 5th graders had a bad day.  Bad in the way that their class mean for their Kakooma score was higher than they wanted it to be.  And maybe even high enough that the 4th graders could beat them.  This was a problem!
One of the thinkers in the group wondered if we could use the class median instead. I’m always open to a good math discussion, so I posed the problem: “Which score would you like to record, the mean or the median?” 
This idea kicked off a long discussion of mean and median.  Those who didn’t remember those terms were quick to ask and re-discover their meanings.  How do you find the median? As they soon realized, the outliers do not affect the median. That was quite the revelation, as we had a significant outlier.  (They know outliers from using the word every week – the outlier gets another turn. Yes, they remember that!)
My students are learning these difficult math vocabulary words by using them often in situations that are meaningful to them.  These words in isolation or on a quiz at the end of the unit are extremely difficult for students to learn.  But these kids, they know them!  I know that next week everyone will remember what a median is and how to find it.  Then, they can decide which description of “average” they want to use, mean or median.  Yes it does matter!
How do your students internalize difficult vocabulary or difficult concepts? Please share your ideas here!

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