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Grade 6 · Maths · Lessons
Which number tells the story?
📊dots⚖️mean🎯median🏔️far dot
Which number tells the story?
The big ideaLook at the dots first. The shape and the job pick the number.

How it works

Look at the dots first. The shape and the job pick the number.

If the data is fairly even, the mean and the median are about the same.

One far-away dot pulls the mean, so the median is a better choice then.

Even data• mean and median agree• either worksOne far dot• the mean is pulled• use the median
Pick the measure.

Example 1: About the same

  1. Minutes: 19, 17, 16, 16, 18, 13.
  2. The mean and the median are close.
  3. Either number tells the story.

Example 2: One far dot

  1. Heights are all near 55 except one 66.
  2. The 66 pulls the mean up.
  3. The mean is a poor choice here.

Example 3: Why

  1. A single far-away value changes the mean a lot.
  2. The median stays in the middle.
  3. Use the median.

Words to know

outlier
A value far from the others.
measure of center
A number, like mean or median, that tells the middle.

Watch out

Try it

  1. Which is pulled by one very big value: mean or median?
  2. When are the mean and median about the same?
  3. What should you look at first?
  4. Which is better with one far-away dot?
Answers: 1. mean · 2. when the data is fairly even · 3. the dots · 4. the median
For grown-upsCompare the mean and median of incomes in a made-up town with one very rich person.
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