Statistics and Probability / Mean as Fair Share

Understanding

This lesson supports the transition from representing data in bar graphs to representing the data on a number line.

What to look for

The mean is often called the average. Students should recognize the mean as a convenient summary statistic that is used extensively in the world around them.

Sample Assessment

What is the mean of the numbers: 4, 8, 3, 2, 5, 8, 12? 
a. 4 
b. 5
c. 6
d. 7
e. 8

Answer: c) 6

The Big Idea

The concept of “fair share” can be developed in two different ways: 1) those with the most give something to those with the least until everyone has the same amount or 2) total all the contributions and divide the total equally among the contributors.

What are the students doing?

Students investigate the standard definition of mean by totaling the number of bags of dog food and sharing the amount equally between the number of dogs.

What is the teacher doing?

Give students time to repeat the activity and reflect on their observations before discussing as a group.