Lesson 8: Describe Data Using the Mean6.DS.4

I can…

I can determine the mean of a data set, use a target mean to find a missing value, and explain the mean as the fair share and the balance point of the data.

Key words

• Mean — Add all the numbers, then divide by how many.
• Average — The amount each one gets when the total is shared equally.
• Measure of center — One number that tells what is typical.
• Balance point — The point where the data evens out. It is the mean.
• Data set — All the values that were collected.
• Target mean — The mean you want to reach.
• Target total — The total the data must add up to.

Steps

1. Miguel's 4 days of earnings are shown with counters. When I combine all of the counters, there are 60 of them, which means Miguel earned $60 in all.
2. Now I redistribute the 60 counters equally among the 4 days. Each of the 4 groups ends up with 15 counters.
3. The arithmetic does exactly the same thing: I find the total, 60, and divide it by the number of days, 4. So 60 ÷ 4 = 15.
4. We can use $15 to describe Miguel's typical daily earnings. That leveled value is the mean.

Try it

Leo read 9, 15, 11, and 17 pages on four nights. What is the mean number of pages he read each night?

Check your answer

13

Add the values: 9 + 15 + 11 + 17 = 52. There are 4 values, so the mean is 52 ÷ 4 = 13 pages.

Sentence starter

I know ___ because ___.

Goal: I can explain my reasoning using the words mean, average, measure of center, balance point, and data set.