michael sylvester wrote: > > I can not remember ever being asked to describe an exam results in > terms of the medianor mode but it seems that everyone is interested in > the mean (average) performance of the class. Why isn't knowing the > mode and the median just as important? One is more likely to come > across "median income" than "median class performance" or "modal class > performance". >
I regularly use the median in describing my grade distribution, and I do it for exactly the same reason one should look at median (rather than mean) income: the distribution is typically highly skewed. A reasonable grade distribution looks much worse (for the students) than it really is if a couple of 8s and 13s drag the mean down. There is no reason that these students' grades should have any more impact on the average than those of students who got 38 or 43. So I usually use the median, to show students where the middle of the grade distribution was. Grade inflation of recent years has made the skew worse even worse. Average grades "should" be at 50. But, alas, we are stuck with what we are stuck with, so we have to use the best statistics we can find. And the best for central tendency in grade distributions is the median. Chris Green York U. Toronto ============ --- You are currently subscribed to tips as: [email protected]. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=2161 or send a blank email to leave-2161-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
