Overview

Students create a stem-and-leaf plot using the number of calories in fast-food breakfasts.

Objective

Students will understand stem-and-leaf plots, with stems in the hundredths place.

Standards Address

Mathematics — Data Analysis

Grade 7

Data Collection, Benchmark A

01. Read, create and interpret box-and-whisker plots, stem-and-leaf plots, and other types of graphs, when appropriate.

Materials

• Rulers

Procedure

1. To start this lesson, show the class an example of what a stem-and-leaf plot looks like. One example might be test scores.

2. Ask a few willing students to find their grades and explain how they found it to the class. Students will learn very quickly how to read this plot.

3. Explain a little about the plot:

The stem can be whatever you determine it to be and the leaves are the remainder of the numbers.

There is a legend to explain the plot.

Generally the plot is written twice, once with the leaves in any order and secondly with the leaves in order from smallest to largest.

4. Distribute the student handout and ask students to make a stem-and-leaf plot using the data given.

5. Remind the students of the need to make a legend explaining the data and to include a title.

6. When this has been completed, give the students the data about the calories in fast-food sandwiches.

7. Introduce the concept of back-to-back stem-and-leaf plots.

8. Have the students complete the graph by plotting the sandwich calories on the left. Review putting the second part of the legend.

9. Ask students to write at least two comparisons between the calories in the breakfast items and the sandwiches.

Answers

Evaluation