Monday, February 4, 2013

Why it's been a while, and will be a while longer

Hannah, a lovely distraction born December 20, 2012 - here 6 weeks old
In case anyone is wondering, the longer-than-usual gap between posts is due to the above tiny but huge bundle of joy. I'm on parental leave from work until August this year, and am too busy with baby to think or write about teaching.

Although... while I was still pregnant and teaching, I realized that pregnancy and child-rearing presents the curious parent with lots of authentic mathematical questions of varying complexity and difficulty. Here are some preliminary notes on ideas:

  • What are the chances of getting pregnant? Contraceptive technology offers a summary table, which informs us about how many women per year, using each of the methods, gets pregnant. How do we translate that into risk of pregnancy per "occasion"? 
  • What are the chances of getting pregnant when one tries? This somewhat depressing graph implies that the chances decrease for each month one is trying, but why? And isn't there a problem with the graph?
  • Miscarriage is such an ugly word, but let's face it: most pregnant women worry at some point or other about whether they'll get to keep the baby. Data on spontaneous abortion (not any less ugly) naturally leads to a discussion about conditional probability, wikipedia has some interesting numbers to work with under the subheading epidemiology. There's also this great example of a function of several variables (maternal and paternal age). 
  • Once pregnant, when will the baby be born? This site has statistical table and graphs for the distribution and cumulative distribution for births after 35 weeks, and can be used to investigate questions of conditional probability ("If you're already at 39 weeks, what are the chances the baby will be born within the next week?") as well as cumulative frequency, probability distributions, normal distribution (although it's more likely to be log-normal, but oh well...) and many other topics within probability and statistics. For fun, one could also check and discuss any discrepancies between the answers arrived at in class and the numbers of the complete statistical table here.
  • How do babies grow before and after birth? From the stats on this site students could practice creating normal distributions for weight, length, and other values and thereby gain more familiarity with multiple representations involving the normal (log-normal) distribution. WHO offers growth charts used by health professionals world-wide, and this BBC page discusses their usefulness and why they needed to be updated.  
There is lots more that can be done with pregnancy and baby health and growth data (for example the birthday problem!), and I think I would be able to form an entire unit on probability and descriptive and inferential statistics based on such data. While not all students will be intrinsically interested in this application, it does seem likely that many will find the experience useful some time in the future. 

Right, little mewing noises from the bedroom let me know that time's up. 
Have a great time teaching, everyone!


  1. Oh Julia, I'm so happy for you!

    (I started spending lots of time online when my son was taking naps as a baby. I'm a single parent, and I would have been so isolated without the internet.)

  2. Hi, Julia,


    I came across your blog via David Wees, and as a fellow mathematics educator (even though you're on leave!), I thought you might be able to help in spreading the word about an educational TV show for preteens about math that we're putting together. "The Number Hunter" is a cross between Bill Nye The Science Guy and The Crocodile Hunter -- bringing math to children in an innovative, adventurous way. I’d really appreciate your help in getting the word out about the project.

    I studied math education at Jacksonville University and the University of Florida. It became clear to me during my studies why we’re failing at teaching kids math. We're teaching it all wrong! Bill Nye taught kids that science is FUN. He showed them the EXPLOSIONS first and then the kids went to school to learn WHY things exploded. Kids learn about dinosaurs and amoeba and weird ocean life to make them go “wow”. But what about math? You probably remember the dreaded worksheets. Ugh.

    I’m sure you know math is much more exciting than people think. Fractal Geometry was used to create “Star Wars” backdrops, binary code was invented in Africa, The Great Pyramids and The Mona Lisa, wouldn’t exist without geometry.
    Our concept is to create an exciting, web-based TV show that’s both fun and educational.

    If you could consider posting about the project on your blog, I’d very much appreciate it. Also, if you'd be interested in link exchanging (either on The Number Hunter site, which is in development, or on which is a well-established site with 300,000 page views a month) please shoot me an email. We're also always looking for input and ideas from other math educators!

    Thanks in advance for your help,


  3. Dear Julia,

    As a proponent of math education in the United States, we need your help to promote our nationwide math competition by blogging or posting about it on your blog/forum.

    As you probably already know, despite the fact that the US spends the most money on education per capita, our students are ranked 25th globally for math proficiency. The MATHCOUNTS Foundation is a nonprofit dedicated to improving that statistic. MATHCOUNTS’ third annual “ Math Video Challenge” is a math competition for 6th to 8th graders that encourages student innovation as they create and star in their own math videos, thus exciting them to pursue higher education in math.

    As the webmaster of this awesome blog, we are asking you to help support this effort by mentioning us in your next blog or forum post or promoting our logo with a link to the site. So far this contest has gathered over 500 submissions and millions of views on the videos. Our goal this year is this year is to do even better. With your help, we are confident we will reach this goal.

    For more information on MATHCOUNTS or the Math Video Challenge, visit our webpages at and

    Jake Byrnes