Worksheets · Statistics

Interquartile range worksheet

Order the data and find the median. Q1 is the median of the lower half and Q3 the median of the upper half, the middle value itself left out of both when the count is odd. The interquartile range is Q3 minus Q1: how wide the middle half of the data is, which outliers cannot stretch.

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Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep

Sigma Prep · sigmaprep.io/worksheets

Name

Interquartile Range

Date Period

Find the interquartile range of each set.

  1. Find the interquartile range: 2,  4,  5,  7,  8,  15,  15
  2. Find the interquartile range: 17,  20,  20,  25,  26,  29,  31
  3. Find the interquartile range: 7,  8,  10,  11,  14,  15,  20,  20,  21
  4. Find the interquartile range: 12,  19,  19,  21,  24
  5. Find the interquartile range: 17,  17,  19,  19,  19,  23,  24,  28,  32
  6. Find the interquartile range: 4,  10,  10,  12,  14
  7. Find the interquartile range: 14,  17,  18,  28,  28
  8. Find the interquartile range: 5,  7,  13,  15,  15
  9. Find the interquartile range: 10,  10,  11,  12,  27
  10. Find the interquartile range: 17,  18,  20,  30,  30
  11. Find the interquartile range: 14,  16,  25,  25,  25
  12. Find the interquartile range: 11,  16,  17,  19,  19,  20,  24
  13. Find the interquartile range: 4,  4,  5,  7,  11,  16,  23
  14. Find the interquartile range: 1,  2,  4,  6,  8,  9,  12,  15,  15
  15. Find the interquartile range: 2,  4,  4,  5,  10,  11,  11,  11,  23
  16. Find the interquartile range: 1,  1,  4,  10,  11,  14,  15
  17. Find the interquartile range: 16,  20,  23,  23,  28
  18. Find the interquartile range: 13,  18,  18,  22,  24
  19. Find the interquartile range: 7,  15,  15,  16,  17
  20. Find the interquartile range: 7,  7,  7,  12,  17

Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep

Sigma Prep · sigmaprep.io/worksheets

Name

Interquartile RangeAnswer keyVersion 1

Date Period

Find the interquartile range of each set.

  1. Find the interquartile range: 2,  4,  5,  7,  8,  15,  1511
  2. Find the interquartile range: 17,  20,  20,  25,  26,  29,  319
  3. Find the interquartile range: 7,  8,  10,  11,  14,  15,  20,  20,  2111
  4. Find the interquartile range: 12,  19,  19,  21,  247
  5. Find the interquartile range: 17,  17,  19,  19,  19,  23,  24,  28,  328
  6. Find the interquartile range: 4,  10,  10,  12,  146
  7. Find the interquartile range: 14,  17,  18,  28,  2812.5
  8. Find the interquartile range: 5,  7,  13,  15,  159
  9. Find the interquartile range: 10,  10,  11,  12,  279.5
  10. Find the interquartile range: 17,  18,  20,  30,  3012.5
  11. Find the interquartile range: 14,  16,  25,  25,  2510
  12. Find the interquartile range: 11,  16,  17,  19,  19,  20,  244
  13. Find the interquartile range: 4,  4,  5,  7,  11,  16,  2312
  14. Find the interquartile range: 1,  2,  4,  6,  8,  9,  12,  15,  1510.5
  15. Find the interquartile range: 2,  4,  4,  5,  10,  11,  11,  11,  237
  16. Find the interquartile range: 1,  1,  4,  10,  11,  14,  1513
  17. Find the interquartile range: 16,  20,  23,  23,  287.5
  18. Find the interquartile range: 13,  18,  18,  22,  247.5
  19. Find the interquartile range: 7,  15,  15,  16,  175.5
  20. Find the interquartile range: 7,  7,  7,  12,  177.5

Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep

How to do these

Find the interquartile range: 3,;4,;5,;7,;10,;10,;10

  1. The median is 7. The lower half is 3, 4, 5 and the upper half 10, 10, 10.
  2. Q1 = 4 and Q3 = 10.

The answer is 6.

Where students go wrong

Including the median in both halves when the count is odd. It belongs to neither, and the quartiles move if it is counted.

Also called IQR, quartiles, Q1 and Q3 or measures of spread.

Questions about these worksheets

Yes. Every interquartile range sheet is free to print and free to download as a PDF. There is no account to make, no email to hand over and no limit on how many you take.

Yes. The answer key prints on a second page, and you can choose whether it shows each question beside its answer or just the answers in a list.

Yes. Print straight from the page, or download the PDF and print that. The sheet is laid out for paper rather than squeezed off a screen, so there is room to work under each question, and the answer key comes out on its own page.

Statistics is usually taken around 11th or 12th grade, though schools vary and plenty of students meet it earlier or later. Pick the difficulty rather than the grade: the easy level suits a first lesson on it, the hard level suits review before a test.

Yes, as many as you like. The questions are built fresh each time rather than picked from a fixed set of files, so pressing Generate gives a new sheet. That is what you want for a second class, a retake, or two students sitting next to each other.

That is the closest comparison, and Kuta Software is good software. It is also paid software you install on a computer. These worksheets run in a browser tab for free, with no account and nothing to install. Like Kuta, the interquartile range questions are generated when you ask for them rather than pulled from a fixed set of files, so two classes never get the same sheet, and the answer key comes with it.

Yes. There are three levels, and you can tick more than one for a sheet that mixes them, in which case the questions come out easiest first. The harder levels are not just larger numbers: they ask for something the easy ones do not.

Including the median in both halves when the count is odd. It belongs to neither, and the quartiles move if it is counted.