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7th grade · Math · Unit 12 of 15

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.

Minnesota K-12 Academic Standards benchmark: 7.1.1.4 · the center, spread and shape of a data distribution

How we explain it

Children can open this short lesson before they practice.

  1. Mean: add the values and divide by how many there are.
  2. Median: the middle value in order. Range: greatest − least.
  3. 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

Center & Spread in Minnesota

In the Minnesota K-12 Academic Standards, this is unit 12 of 15 in 7th grade Math, after Mean, Median & Mode and before Multiply & Divide Signed Numbers.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Minnesota Department of Education (MDE)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Which is a statistical question?

    • How tall is the school flagpole?
    • How many hours did I sleep last night?
    • How many days are in a leap year?
    • How many books did each student in our grade read this month?

  2. Question 2

    What is the mean of 10, 3, 13, 15, 9?

    • 11
    • 8
    • 10
    • 7
    • 12

  3. Question 3

    What is the range of 59, 41, 25, 44, 18, 9?

    • 59
    • 50
    • 33
    • 51
    • 49

  4. Question 4

    What is the interquartile range (IQR) of 37, 7, 25, 23, 7, 39, 7, 37?

    • 30
    • 37
    • 7
    • 27
    • 32

  5. Question 5

    The data 11, 11, 13, 14, 19, 88 has one very large value. Which measure describes the typical value best?

    • The range
    • The mean
    • The median

  6. Question 6

    What is the median of 17, 4, 25, 5, 3?

    • 5
    • 4
    • 6
    • 25
    • 5.5

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