Units Matter

As someone who has long considered himself a “pure math” person, as opposed to more of a “science” person, I never really cared much about the units of expressions; kilograms, meters, Newtons, and the like.  The numbers were all I ever really cared about. Well now I see what can happen when this attitude is taken too far.

signs

It took me about 3 days of driving around Puerto Rico before I realized that speed limits were posted in miles per hour and mile markers were posted in kilometers. Driving around a foreign country (territory?) is challenging enough without having to perform a bunch of conversions in your head.

Just to further complicate matters, plenty of signs left it open to driver interpretation.

velocidad maxima

Math Quiz: NYT Learning Network

google searchThrough Math for America, I am part of an on-going collaboration with the New York Times Learning Network.  My latest contribution, a Test Yourself quiz-question, can be found here:

http://learning.blogs.nytimes.com/2011/03/16/test-yourself-math-march-16-2011/

This question is based on Google-search statistics, specifically how much traffic is driven to the top two Google search results.

Based on the numbers, it’s easy to see why companies are willing to bend the rules to climb the rankings!

Math Lesson: NCAA Rankings

ncaa trophyMy latest contribution to the NYT Learning Network is a mathematics lesson build around the way NCAA basketball teams are ranked.

http://learning.blogs.nytimes.com/2011/03/14/whos-no-1e-investigating-the-mathematics-of-rankings/

Quantitative rankings are ubiquitous these days, and they are playing an ever-increasing role in teaching.  Colleges have been “ranked” by publications for years, but now public schools are being assigned grades and even teachers can be ranked according to complicated, and often controversial, formulas.

In this lesson, students are tasked with creating their own rankings of the sports teams.

Looking only at winning percentage, therefore, may not be a fair assessment of who is better than whom: if Team X plays in a relatively weak conference, and Team Y plays in a relatively strong conference, it will be easier for Team X to record wins. This is similar to the idea of ranking students based on unweighted G.P.A.’s: such a system may well reward students who take relatively easy classes and put students with more challenging programs at a disadvantage.

So, student pairs should explore approaches to addressing this issue by attempting to quantify a team’s strength of schedule, thereby creating a ranking system that will take into consideration the quality of each team’s opponents.

These rankings only make as much sense as the underlying mathematics.  Hopefully, through investigating the way the NCAA ranks basketball teams, teachers and students can learn to deconstruct these ranking systems and better evaluate their utility .

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