Grade 6 · Maths · Lessons
How spread out
📏range📦box🎯median↔️spread
How spread out?The big ideaThe range is the biggest less the smallest. The box holds the middle half.
How it works
The range is the biggest number less the smallest.
The median is the middle number. The box holds the middle half of the data: from Q1 to Q3.
The mean absolute deviation tells how far the data is from the mean on average.
Example 1: Find the median
- Heights: 54, 59, 60, 60, 61, 65, 66.
- Put them in order and take the middle one.
- The median is 60.
Example 2: The range
- The smallest is 54 and the biggest is 66.
- 66 − 54 = 12.
- The range is 12.
Example 3: Mean absolute deviation
- Data: 63, 59, 59, 65, 64. The mean is 62.
- Distances from 62: 1, 3, 3, 3, 2. They add to 12.
- 12 ÷ 5 = 2.4, so the MAD is 2.4.
Words to know
- range
- The biggest value minus the smallest.
- median
- The middle value when ordered.
Watch out
- Order the data first.
- With an even number of values, the median is halfway between the two middle ones.
- Distances are never negative.
Try it
- What is the range of 3, 7, 9, 12?
- What is the median of 2, 5, 8?
- What is the median of 4, 6, 8, 10?
- What does the box in a box plot hold?
Answers: 1. 9 · 2. 5 · 3. 7 · 4. the middle half of the data
For grown-upsCollect the heights of family members and find their range and median.