Histograms, mean, median and mode, Excel

That’s a substantial agenda. I’m also moving as far as I comfortably can to flipping the classroom, as described in this New York Times blog post. I will try to have the students read the text at home and use class time work exercises, in groups.

But I needed to start today presenting material. Put up the Wing Aero salary histogram, explained mode, median and mean (in that order!),  I think I made sense – but then I always do. I noted that taking the mode, median and mean of the data column that lists the contents of the bins makes no sense and gives meaningless answers – noting that it’s a very common error on exams. I fully expect my warning to go unheeded.

Then I had them work on the income distribution Exercise (6.14.20). The struggle started with trying to reproduce the graphic. The two major problems were (as expected) Excel treating the bin labels as data (when they were entered numerically, with no text “k”), and then treating the entry 10-20 as October 20. So we had a brief digression on how to deal with the times when Excel’s attempt to guess what you mean is wrong.

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