6th grade · Math · Unit 14 of 17
Center & Spread
Mean, median, range and IQR
What your child practices
Telling a statistical question from a regular question, and describing data with the mean, median, range and interquartile range.
Oregon State Standards learning standard: 6.DR.A.1; 6.DR.C.3; 6.DR.D.4 · recognizing statistical questions and summarizing data with measures of centre and variability
How we explain it
Children can open this short lesson before they practice.
- Mean: add the values and divide by how many there are.
- Median: the middle value in order. Range: greatest − least.
- IQR: Q3 − Q1, the spread of the middle half.
Example: What is the mean of 4, 7, 9 and 12? 4 + 7 + 9 + 12 = 32. 32 ÷ 4 = 8. Answer: 8
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
What is the interquartile range (IQR) of 29, 37, 37, 21, 28, 40, 23, 17?
- 15
- 23
- 22
- 12
- 37
15
Hint: Order the data. Q1 = 22 (middle of the lower half), Q3 = 37 (middle of the upper half). IQR = Q3 − Q1.
Question 2
What is the mean of 3, 18, 5, 16, 13?
- 13
- 15
- 12
- 11
- 14
11
Hint: Add them (55) and divide by 5.
Question 3
The data 10, 13, 16, 17, 18, 88 has one very large value. Which measure describes the typical value best?
- The mean
- The range
- The median
The median
Hint: One extreme value pulls the mean and range a long way, but the median barely moves.
Question 4
Which is a statistical question?
- How tall is the school flagpole?
- How tall are the sunflowers in the school garden?
- How many hours did I sleep last night?
- How many students are in Room 12?
How tall are the sunflowers in the school garden?
Hint: A statistical question expects answers that vary, so you collect data to answer it.
Question 5
What is the range of 25, 27, 60, 27, 4, 10?
- 56
- 57
- 26
- 53
- 60
56
Hint: Range = greatest − least.
Question 6
What is the median of 1, 30, 18, 2, 16, 23, 14?
- 16.5
- 16
- 2
- 15
- 17
16
Hint: Put the numbers in order. The median is the middle one (or the mean of the two middle ones).