Interquartile range worksheet for Algebra 1

Algebra 1 uses the interquartile range to compare data sets and to test for outliers. A value below Q1 - 1.5 × IQR or above Q3 + 1.5 × IQR counts as an outlier, and the same quartiles are the edges of the box in a box plot.

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

Select your difficulty

Pick more than one for a sheet that mixes them.

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Sigma Prep · sigmaprep.io/worksheets Name Interquartile Range Date Period Find the interquartile range, or the outliers, of each set. Find the interquartile range Find the interquartile range: $6,$ $6,$ $6,$ $7,$ $8,$ $19,$ $20,$ $20,$ $25$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $17, 17, 26, 29, 31$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $11,$ $12,$ $13,$ $13,$ $14,$ $15,$ $19,$ $20,$ $21,$ $22$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $15, 17, 22, 23, 25, 25, 27$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $17, 18, 24, 27, 29, 29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $10,$ $11,$ $12,$ $18,$ $19,$ $21,$ $21,$ $24$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $15,$ $15,$ $16,$ $16,$ $27,$ $29,$ $29,$ $29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $4, 9, 11, 11, 15$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $1,$ $2,$ $5,$ $5,$ $5,$ $10,$ $10,$ $10,$ $10,$ $22$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find the interquartile range: $3, 3, 3, 5, 7, 9, 13, 17, 30$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Find outliers with the $1.5 \times \text{IQR}$ rule Use the $1.5 \times$ IQR rule to find any outliers: $11, 14, 16, 18, 18, 24, 25$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $9,$ $11,$ $12,$ $13,$ $13,$ $14,$ $17,$ $20,$ $21,$ $30,$ $37$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $7,$ $8,$ $9,$ $11,$ $12,$ $13,$ $14,$ $18,$ $19,$ $19$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $11,$ $12,$ $12,$ $14,$ $19,$ $21,$ $23,$ $41$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $1, 8, 8, 9, 14, 29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $14,$ $16,$ $17,$ $20,$ $21,$ $26,$ $27,$ $27,$ $46$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $17, 19, 23, 23, 28$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $8, 9, 9, 12, 16, 17, 20, 21$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $10,$ $11,$ $12,$ $13,$ $17,$ $18,$ $19,$ $23,$ $23,$ $24,$ $43$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. Use the $1.5 \times$ IQR rule to find any outliers: $8,$ $9,$ $10,$ $14,$ $15,$ $17,$ $17,$ $17,$ $19,$ $35$ . 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 Range

Date Period

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

Find the interquartile range
Find the interquartile range:
$6,$ $6,$ $6,$ $7,$ $8,$ $19,$ $20,$ $20,$ $25$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range:
$17, 17, 26, 29, 31$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range:
$11,$ $12,$ $13,$ $13,$ $14,$ $15,$ $19,$ $20,$ $21,$ $22$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range:
$15, 17, 22, 23, 25, 25, 27$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range:
$17, 18, 24, 27, 29, 29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range:
$10,$ $11,$ $12,$ $18,$ $19,$ $21,$ $21,$ $24$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range:
$15,$ $15,$ $16,$ $16,$ $27,$ $29,$ $29,$ $29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range: $4, 9, 11, 11, 15$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range:
$1,$ $2,$ $5,$ $5,$ $5,$ $10,$ $10,$ $10,$ $10,$ $22$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Find the interquartile range:
$3, 3, 3, 5, 7, 9, 13, 17, 30$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.

Find outliers with the $1.5 \times \text{IQR}$ rule
Use the $1.5 \times$ IQR rule to find any outliers:
$11, 14, 16, 18, 18, 24, 25$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$9,$ $11,$ $12,$ $13,$ $13,$ $14,$ $17,$ $20,$ $21,$ $30,$ $37$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$7,$ $8,$ $9,$ $11,$ $12,$ $13,$ $14,$ $18,$ $19,$ $19$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$11,$ $12,$ $12,$ $14,$ $19,$ $21,$ $23,$ $41$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$1, 8, 8, 9, 14, 29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$14,$ $16,$ $17,$ $20,$ $21,$ $26,$ $27,$ $27,$ $46$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$17, 19, 23, 23, 28$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$8, 9, 9, 12, 16, 17, 20, 21$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$10,$ $11,$ $12,$ $13,$ $17,$ $18,$ $19,$ $23,$ $23,$ $24,$ $43$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.
Use the $1.5 \times$ IQR rule to find any outliers:
$8,$ $9,$ $10,$ $14,$ $15,$ $17,$ $17,$ $17,$ $19,$ $35$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.



Sigma Prep · sigmaprep.io/worksheets Name Interquartile RangeAnswer keyVersion 2 Date Period Find the interquartile range, or the outliers, of each set. Find the interquartile range Find the interquartile range: $6,$ $6,$ $6,$ $7,$ $8,$ $19,$ $20,$ $20,$ $25$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $14$ Find the interquartile range: $17, 17, 26, 29, 31$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $13$ Find the interquartile range: $11,$ $12,$ $13,$ $13,$ $14,$ $15,$ $19,$ $20,$ $21,$ $22$ . 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: $15, 17, 22, 23, 25, 25, 27$ . 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: $17, 18, 24, 27, 29, 29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $11$ Find the interquartile range: $10,$ $11,$ $12,$ $18,$ $19,$ $21,$ $21,$ $24$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $9.5$ Find the interquartile range: $15,$ $15,$ $16,$ $16,$ $27,$ $29,$ $29,$ $29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $13.5$ Find the interquartile range: $4, 9, 11, 11, 15$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $6.5$ Find the interquartile range: $1,$ $2,$ $5,$ $5,$ $5,$ $10,$ $10,$ $10,$ $10,$ $22$ . 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: $3, 3, 3, 5, 7, 9, 13, 17, 30$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $12$ Find outliers with the $1.5 \times \text{IQR}$ rule Use the $1.5 \times$ IQR rule to find any outliers: $11, 14, 16, 18, 18, 24, 25$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None Use the $1.5 \times$ IQR rule to find any outliers: $9,$ $11,$ $12,$ $13,$ $13,$ $14,$ $17,$ $20,$ $21,$ $30,$ $37$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $37$ Use the $1.5 \times$ IQR rule to find any outliers: $7,$ $8,$ $9,$ $11,$ $12,$ $13,$ $14,$ $18,$ $19,$ $19$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None Use the $1.5 \times$ IQR rule to find any outliers: $11,$ $12,$ $12,$ $14,$ $19,$ $21,$ $23,$ $41$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $41$ Use the $1.5 \times$ IQR rule to find any outliers: $1, 8, 8, 9, 14, 29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $29$ Use the $1.5 \times$ IQR rule to find any outliers: $14,$ $16,$ $17,$ $20,$ $21,$ $26,$ $27,$ $27,$ $46$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $46$ Use the $1.5 \times$ IQR rule to find any outliers: $17, 19, 23, 23, 28$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None Use the $1.5 \times$ IQR rule to find any outliers: $8, 9, 9, 12, 16, 17, 20, 21$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None Use the $1.5 \times$ IQR rule to find any outliers: $10,$ $11,$ $12,$ $13,$ $17,$ $18,$ $19,$ $23,$ $23,$ $24,$ $43$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $43$ Use the $1.5 \times$ IQR rule to find any outliers: $8,$ $9,$ $10,$ $14,$ $15,$ $17,$ $17,$ $17,$ $19,$ $35$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $35$ Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep

Sigma Prep · sigmaprep.io/worksheets

Name

Interquartile RangeAnswer keyVersion 2

Date Period

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

Find the interquartile range
Find the interquartile range:
$6,$ $6,$ $6,$ $7,$ $8,$ $19,$ $20,$ $20,$ $25$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $14$
Find the interquartile range:
$17, 17, 26, 29, 31$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $13$
Find the interquartile range:
$11,$ $12,$ $13,$ $13,$ $14,$ $15,$ $19,$ $20,$ $21,$ $22$ . 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:
$15, 17, 22, 23, 25, 25, 27$ . 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:
$17, 18, 24, 27, 29, 29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $11$
Find the interquartile range:
$10,$ $11,$ $12,$ $18,$ $19,$ $21,$ $21,$ $24$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $9.5$
Find the interquartile range:
$15,$ $15,$ $16,$ $16,$ $27,$ $29,$ $29,$ $29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $13.5$
Find the interquartile range: $4, 9, 11, 11, 15$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $6.5$
Find the interquartile range:
$1,$ $2,$ $5,$ $5,$ $5,$ $10,$ $10,$ $10,$ $10,$ $22$ . 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:
$3, 3, 3, 5, 7, 9, 13, 17, 30$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $12$

Find outliers with the $1.5 \times \text{IQR}$ rule
Use the $1.5 \times$ IQR rule to find any outliers:
$11, 14, 16, 18, 18, 24, 25$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None
Use the $1.5 \times$ IQR rule to find any outliers:
$9,$ $11,$ $12,$ $13,$ $13,$ $14,$ $17,$ $20,$ $21,$ $30,$ $37$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $37$
Use the $1.5 \times$ IQR rule to find any outliers:
$7,$ $8,$ $9,$ $11,$ $12,$ $13,$ $14,$ $18,$ $19,$ $19$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None
Use the $1.5 \times$ IQR rule to find any outliers:
$11,$ $12,$ $12,$ $14,$ $19,$ $21,$ $23,$ $41$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $41$
Use the $1.5 \times$ IQR rule to find any outliers:
$1, 8, 8, 9, 14, 29$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $29$
Use the $1.5 \times$ IQR rule to find any outliers:
$14,$ $16,$ $17,$ $20,$ $21,$ $26,$ $27,$ $27,$ $46$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $46$
Use the $1.5 \times$ IQR rule to find any outliers:
$17, 19, 23, 23, 28$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None
Use the $1.5 \times$ IQR rule to find any outliers:
$8, 9, 9, 12, 16, 17, 20, 21$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd.None
Use the $1.5 \times$ IQR rule to find any outliers:
$10,$ $11,$ $12,$ $13,$ $17,$ $18,$ $19,$ $23,$ $23,$ $24,$ $43$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $43$
Use the $1.5 \times$ IQR rule to find any outliers:
$8,$ $9,$ $10,$ $14,$ $15,$ $17,$ $17,$ $17,$ $19,$ $35$ . For quartiles, split the data at the median, and leave the median out of both halves when the count is odd. $35$

How to do these

Use the $1.5 \times$ IQR rule to find any outliers:
$2, 10, 11, 12, 13, 14, 15$

The median is 12, so Q1 = 10 and Q3 = 14, and the IQR is 4.
1.5 × 4 = 6, so the fences are 10 - 6 = 4 and 14 + 6 = 20.
Only 2 is outside them.

The answer is $2$ .

Where students go wrong

Calling a value an outlier because it looks far away. Work out the fences first; here the lower fence is 4, so 2 is an outlier but 5 would not be.

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 $1.5 \times$ 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.

Algebra 1 is usually taken around 8th or 9th 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.

Interquartile range worksheet for Algebra 1

Select your difficulty

Find the interquartile range

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

Find the interquartile range

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

How to do these

Where students go wrong

What you can put on this worksheet

Questions about these worksheets

Are these interquartile range worksheets free?+

Do the interquartile range worksheets come with an answer key?+

Are these interquartile range worksheets printable?+

What grade are these interquartile range worksheets for?+

Can I get a different version of the same interquartile range worksheet?+

Is this a free alternative to Kuta Software for interquartile range?+

Can I choose how hard the interquartile range questions are?+

What kinds of question are on a interquartile range worksheet?+

What do students get wrong with interquartile range?+

Find outliers with the $1.5 \times \text{IQR}$ rule

Find outliers with the $1.5 \times \text{IQR}$ rule