Month: November 2007

Total 36 Posts

How Old Is Tiger Woods?

If you asked me to name something that’d trigger a teenager’s passion, I wouldn’t leap at “Correctly Guessing a Has-Been Celebrity’s Age” straight away. But there they were, hollering, competing, and rallying over near misses like frat boys over fantasy football.

  • You have your students make three columns: Name, Guess, and Actual.
  • You project twenty-or-so celebrities (a broad range of ages) onto the wall. You have ’em guess the age out loud.
  • As they toss out guesses you say, “It’s probably a bad idea to toss out your guess. We’re all competing for the title of Best Age Guesser. Keep ’em close.”
  • You keep projecting, they keep guessing. Maybe you ask ’em, “twenties or thirties or forties?” to keep ’em participating together.
  • Then you go back through and give the ages. They write those under the “Actual” column. Watch ’em get crazy here, freaking out ’cause they were only three years off Natalie Portman’s age. Watch some of ’em blow Nelson Mandela by decades.

Enter the mathematics here:

  • You ask, “how do we decide who guessed the best?” Expect intial suggestions like, “Whoever guessed the most right.” and “Whoever got closest to each age.”
  • Take care of that first suggestion by asking who got the most right (Vicki, let’s say) and then ask the class, “Can we stop searching for the best guesser now? Is Vicki guaranteed? Why not?”
  • Ask for clarification on the second suggestion. Get to a place where they’re subtracting the actual answer from the guess, getting negative numbers for underguesses and positive number for overguesses.

Make the math as hard or as easy as you want here.

Algebra and Below:

  • Someone will suggest you add the new column of numbers up. You ask, “What number do we want there?”
  • Someone’ll suggest “Zero.” You talk about the girl who overguesses Tiger Woods by 30 years and underguesses Oprah by 30 years.

    Girl has a zero but couldn’t guess your age if you handed her your driver’s license.

  • “So what do we do?”
  • Drop the negatives. It doesn’t matter if you guess over or under, only that you’re off.
  • Have them find the mean of their new column, full of positives. What does it mean? (The average number of years they were off per guess.)
  • Ask if it means they guessed over or under on average. (Can’t tell, we dropped the negatives.)
  • Have them find the average including the negatives. (“Who guessed under on average? Who guessed over?”)

Algebra II:

  • Connect this to absolute value.


  • Talk about why the square of the differences is preferable to their absolute values. (x2 is differentiable where absolute value isn’t.)

Give the winner a fun-sized candy bar. Let her select a celebrity for inclusion in next year’s lineup.


Credit Where It’s Due:

Got this idea from my ed-school mentor several years back. Yo, AB, I still use your stuff, man.

[Update: Matt has some pretty priceless extensions to this lab.]

How does the Mean and Median of all student guess do in this competition?

Creating a histogram of the guesses.

Looking at the standard deviation of the student guess. Do standard deviations vary with the age of the person.

And I reply:

Oh yeah, that’s great. It’s so clear now. I need to feature as many or more celebrities as there are students in the class. After the main event then I assign a celebrity to each student, they collect the guesses from around the class and perform a statistical analysis. Maybe I have Keynote slides set up so they punch in their data and present it real quick.

For Your Consideration:

Peace and prosperity. Vote dy/dan best new edublog and best individual edublog.

One Day At A Time

  • drove to San Jose Municipal airport sometime around 04h00 PST;
  • gate agent bumped me to first class just before departure, setting the whole trip up on a high shelf from the start;
  • sneered back at the peasantry in economy seating seventeen times over the first twelve minutes of flight;
  • read Andrew Keen’s anti-Web-2.0 anti-fun polemic The Cult of the Amateur 35,000 feet above Utah’s Great Salt Flats, agreeing with much of it, estimating the percent of unhappy edubloggers who read it to be somewhere around 35, finishing it as we taxied into Minneapolis-St. Paul;
  • met my twin sister (last seen: 1.5 years ago) and two cousins (last seen: 10 years ago) in St. Cloud;
  • was introduced by doting grandparents to each of St. Cloud’s 62,000 residents;
  • was asked an awful lot about my job teaching math;
  • saw in College-Aged Cousin diligence, industry, and some other virtues I cherish and covet;
  • experienced an awful moment of clarity;
  • realized I am and have been wasting my diligence and industry in a profession which, by evidence of how it pays its employees (by years and units), doesn’t care about hard work or industry;
  • wrote a letter to the editor of the San Francisco Chronicle entitled “Obituary of a Fourth-Year Teacher” and CC’d my district;
  • licked the stamp;
  • called TMAO, asked him to talk me down;
  • put the letter in a drawer;
  • got flagged for one of TSA’s special security screenings on the flight back which seemed to fit the overall arc of the trip like a glove.

ID115: Pie Charts – Movie Posters

Similar to ID111 but with movie posters. Somewhere in between these two we practiced measuring and drawing angles.

I stressed that I wanted their reaction to the poster itself and not to the movie, which some students doubtlessly hadn’t seen.

I included two of my favorite one sheets. Reactions came back mixed and I lamented silently how NCLB has looted artistic appreciation in our nation’s public school for corporate fun and profit.

Fun questions to ask (again):

  1. Who loved the most one sheets?
  2. Who hated the most one sheets?
  3. Whose one sheet was the most hated?
  4. Whose one sheet was the most liked?

One Sheet Analysis Template (student carries this from desk to desk)
Personal Pie Graph Template (student makes her personal pie graph on this)
One Sheet Analysis Template II (this stays with each one sheet for students to mark)
One Sheet Class Analysis Template (this follows the one sheet from class to class)
The One Sheets We Used (formatting is left as an exercise for the reader)
Student Protractors (print ’em out on overhead transparency)