## Lesson: Sampling Techniques

Developing the Concept

Your students have had an opportunity to investigate selecting samples. Now they can apply their knowledge to a particular experiment.

**Materials:** a paper bag and 84 connecting cubes (56 blue and 28 yellow, or whatever colors are available), counters, or other small objects

**Preparation:** Put the 84 cubes into the paper bag before class begins.

**Prerequisite Skills and Concepts:** Students should be able to set up a proportion and solve it.

**Wrap-Up and Assessment Hints:**

Biologists do a lot of sampling in order to determine the size of a wildlife population or how many specimens of a kind of plant grow in a certain locale. This would be a great opportunity to connect mathematics to science in your classroom. A biologist studying plant life in a forest will take several random samples by staking out a square area called a *quadrat.* The biologist will then classify all the plants in the area of several quadrats to determine what percent of the forest area is covered by the species of plant. Similarly, a biologist wanting to find out how many black bear live in a national park might capture and tag 30 black bears from different areas in the park. The following year he would go back and capture another group of random samples from all across the park. Based on the ratio of tagged bears to total bears captured in the second sample, the biologist could obtain a good estimate of how many bears there were in the whole park.