Worksheets · Pre-Algebra

Interquartile range worksheet for Pre-Algebra

In Pre-Algebra the data sets are short, so finding the interquartile range is mostly careful ordering and finding middles: Q1 is the middle of the lower half and Q3 the middle of the upper half. Half the questions then use the IQR to test for outliers, values more than 1.5 × IQR below Q1 or above Q3.

Also taught in Statistics and Algebra 1, each at its own level and with its own examples.

Select your difficulty

Pick more than one for a sheet that mixes them.

The preview can look cramped on a phone. The PDF and printed sheet come out normal.

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

Sigma Prep · sigmaprep.io/worksheets

Name

Interquartile Range

Date Period

Find the interquartile range, or the outliers, of each set.

  1. Find the interquartile range

    Find the interquartile range:
    2,  3,  6,  6,  6,  8,  11. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  2. Find the interquartile range:
    8,  9,  10,  10,  11,  12. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  3. Find the interquartile range:
    10,  11,  11,  14,  24. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  4. Find the interquartile range:
    2,  3,  3,  4,  10,  10,  10. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  5. Find the interquartile range:
    5,  7,  7,  8,  13,  14. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  6. Find the interquartile range: 3,  6,  6,  7,  8. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  7. Find the interquartile range: 4,  8,  9,  9,  10. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  8. Find the interquartile range:
    7,  9,  10,  13,  13,  14. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  9. Find the interquartile range:
    10,  10,  14,  15,  21. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  10. Find the interquartile range: 4,  4,  6,  10,  11. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.

  1. Find outliers with the 1.5×IQR1.5 \times \text{IQR} rule

    Use the 1.5×IQR rule to find any outliers: 7,  8,  9,  13,  13. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  2. Use the 1.5×IQR rule to find any outliers:
    3,  4,  5,  8,  9,  9,  11. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  3. Use the 1.5×IQR rule to find any outliers:
    2,  4,  5,  6,  8,  8,  9,  18. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  4. Use the 1.5×IQR rule to find any outliers:
    11,  11,  12,  15,  16,  29. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  5. Use the 1.5×IQR rule to find any outliers:
    9,  11,  13,  13,  14,  15,  16. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  6. Use the 1.5×IQR rule to find any outliers:
    7,  9,  9,  12,  14,  15. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  7. Use the 1.5×IQR rule to find any outliers:
    3,  4,  6,  6,  9,  10,  11,  28. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  8. Use the 1.5×IQR rule to find any outliers: 9,  12,  12,  15,  17. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  9. Use the 1.5×IQR rule to find any outliers:
    8,  8,  9,  10,  12,  13,  24. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
  10. Use the 1.5×IQR rule to find any outliers:
    4,  6,  7,  8,  9,  11,  11,  26. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.

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

Sigma Prep · sigmaprep.io/worksheets

Name

Interquartile RangeAnswer keyVersion 3

Date Period

Find the interquartile range, or the outliers, of each set.

  1. Find the interquartile range

    Find the interquartile range:
    2,  3,  6,  6,  6,  8,  11. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    5
  2. Find the interquartile range:
    8,  9,  10,  10,  11,  12. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    2
  3. Find the interquartile range:
    10,  11,  11,  14,  24. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    8.5
  4. Find the interquartile range:
    2,  3,  3,  4,  10,  10,  10. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    7
  5. Find the interquartile range:
    5,  7,  7,  8,  13,  14. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    6
  6. Find the interquartile range: 3,  6,  6,  7,  8. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.3
  7. Find the interquartile range: 4,  8,  9,  9,  10. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.3.5
  8. Find the interquartile range:
    7,  9,  10,  13,  13,  14. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    4
  9. Find the interquartile range:
    10,  10,  14,  15,  21. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    8
  10. Find the interquartile range: 4,  4,  6,  10,  11. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.6.5

  1. Find outliers with the 1.5×IQR1.5 \times \text{IQR} rule

    Use the 1.5×IQR rule to find any outliers: 7,  8,  9,  13,  13. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None
  2. Use the 1.5×IQR rule to find any outliers:
    3,  4,  5,  8,  9,  9,  11. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    None
  3. Use the 1.5×IQR rule to find any outliers:
    2,  4,  5,  6,  8,  8,  9,  18. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    18
  4. Use the 1.5×IQR rule to find any outliers:
    11,  11,  12,  15,  16,  29. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    29
  5. Use the 1.5×IQR rule to find any outliers:
    9,  11,  13,  13,  14,  15,  16. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    None
  6. Use the 1.5×IQR rule to find any outliers:
    7,  9,  9,  12,  14,  15. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    None
  7. Use the 1.5×IQR rule to find any outliers:
    3,  4,  6,  6,  9,  10,  11,  28. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    28
  8. Use the 1.5×IQR rule to find any outliers: 9,  12,  12,  15,  17. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None
  9. Use the 1.5×IQR rule to find any outliers:
    8,  8,  9,  10,  12,  13,  24. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    24
  10. Use the 1.5×IQR rule to find any outliers:
    4,  6,  7,  8,  9,  11,  11,  26. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.    26

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

How to do these

Find the interquartile range:
8,  3,  12,  5,  10,  7

  1. Sort: 3, 5, 7, 8, 10, 12.
  2. Lower half 3, 5, 7 gives Q1 = 5. Upper half 8, 10, 12 gives Q3 = 10.
  3. 10 - 5 = 5.

The answer is 5.

Where students go wrong

Skipping the sort. The quartiles are positions in an ordered list, so taking the middles of the list as written gives the wrong Q1 and Q3.

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

What you can put on this worksheet

Interquartile range
Find the interquartile range:
7,  10,  10,  10,  14,  15. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. → 4
Outliers by the 1.5 x IQR rule
Use the 1.5×IQR rule to find any outliers:
7,  10,  10,  10,  14,  15. For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. → None

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.

Pre-Algebra is usually taken around 7th or 8th 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.

You pick from 2: interquartile range and outliers by the 1.5 x iqr rule. Tick as many as you want and set how many of each, or let it spread them evenly.

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