Box and Whisker

I’m finishing up teaching a unit about probability and data.  We’ve been going fairly slow because some of this stuff confuses ME.  Independent, dependent and compound events, with replacement, without replacement, order does matter, order does not matter…  ugh.

One section focuses on data.  We calculate the mean, median, mode, variance and standard deviation.  I was able to talk with one of my colleagues who teaches the AP Prob and Stats class.  She had a fabulous idea for teaching about box and whisker plots.  So I certainly don’t take credit for this.  But it’s too good not to share.

Have your students line up in order from shortest to tallest.  When they’re all standing there, have them figure out who is the median.  If you have an even number of kids, it will be in between two of them.  Then have them figure out which kids are at quartile 1 and 3.  Everyone in between is the inter-quartile range.  Have them step forward and this is the “box” in your box and whisker plot.  This represents the middle 50% of your data.  The people left are the “whiskers” with your minimum and maximum values on either end.  After you’ve done that once, take out one kid so they have to figure it out with both and even number and an odd number of students.

Another fun activity is when you have them come up with a question to gather data.  It needs to be one with a variety of answers.   How many hours of sleep did you get last night?  How old are you?  How many people live in your house?  They calculate the mean, median and mode and then draw a box and whisker plot and present their findings to the class.  The one that was fun was the group that asked how old we all were.  They calculated the data twice – once including me in their data and the other without my age.  It showed how an outlier can affect the mean and how it changes your box and whisker plot.

I asked the students about the activities and they seemed to be a hit – especially the one with their heights.  It was fun and they liked it.  What more can you ask for?


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