PBS Teachers™

PBS Teachers

Multimedia resources & professional development for America's preK-12 educators.

Mathline

The Smithville Families
Probability

Download PDF Lesson | Get Acrobat
A Printable version of this lesson is available in PDF format.
This requires a free plug-in, Adobe Acrobat Reader.
You can find out if you need it by clicking on the PDF link.

Objective

Students will create the number sequences of Pascal's triangle and discover a relationship that this triangle has to theoretical probability.

Overview of the Lesson

First, students review Pascal’s Triangle by completing and discussing the entries of the first eight rows. They then engage in an activity designed to determine the total number of possible girl/boy combinations in a five-child family. This is accomplished by having students investigate the number and make-up of different five-child families that could be born in a town called Smithville. A coin is used to simulate the births of different children. If the coin shows a head, the child is a girl and if it shows a tail, the child is a boy. The different combinations are presented in an organized manner so that students can discover patterns that will enable them to identify all possibilities. Students are encouraged to look for patterns that will assist them in generating the numbers in subsequent rows of Pascal’s Triangle. Finally, students work collaboratively to address and analyze questions regarding the theoretical probabilities of other multiple-child families using Pascal's Triangle.