Teaching Algebra with Manipulatives

Using Overhead Manipulatives
(Use with Algebra 1, Lesson 2-5)
Measures of Central Tendency
Objective Analyze data using mean, median and mode.
Materials
• transparency pens*
• blank transparency
* available in Overhead Manipulative Resources
Demonstration
Mean, Median and Mode
• Ask students to imagine that they must describe the average student in
the classroom. Have them identify some of the characteristics that might
describe a student. Sample answer: shoe size, height, et al.
• Survey the students. Ask for the following information: age in months,
number of children in the family, height in centimeters. Using a stemand-leaf
plot, record the results on a blank transparency.
Algebra 1—Chapter 2
• Review the definitions of the three measures of central tendency: the
mean, median, and mode. Have students use the stem-and-leaf plot to
help them find the mean, median, and mode of the three categories
surveyed. Ask students which of the three measures best describes each
set of data and why. Answers will vary.
• Ask if this information describes all the students in the school. Answers
will vary.
• Discuss the factors that might prevent this survey from being valid for
the entire school. Answers will vary.
Extension
Analyzing Data
Ask students to suggest ways an advertiser might use the information
collected in this survey.
© Glencoe/McGraw-Hill 45 Teaching Algebra with Manipulatives