Thursday, September 28, 2017

Teach 180: A Distribution of Pennies (Day 21)

Today in Prob/Stat students worked in groups of 3-4 to create a distribution for the ages of pennies.  One group even organized their pennies in a dotplot of pennies.

Once we combined all the data we
had the following dotplot at the front
of the room. (The right tail
ended up at 59, but I erased part of it and then snapped this picture.) There are more younger pennies than older pennies, but it was clear to see that creating a dotplot like this by oneself would not have been very practical.  Our final dotplot had 180 observations!!  Clearly dotplots are better for smaller data sets.   What would be a better way to organize the data?  A histogram!

First we created the histogram by hand and then we used our TI-84's to make the histogram.  Students set the window manually to match the original histogram we made by hand.  Then, we used the Zoom Stat feature.  This allowed the calculator to determine the bar width. But what was the bar width?  6.875 years?  Since penny ages were recorded in years, on a quick glance the histogram at the left makes more sense than the histogram at the right.  Next up?  Measures of center and spread and boxplots.


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