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Dot Plots: Quartiles and Interquartile Range — Easy Worksheet 1
Grade 10 · Whoobee Name: ____________________ Date: __________
Q1 is the median of the lower half of the data and Q3 is the median of the upper half. When there is an odd number of values, leave the median out of both halves. IQR = Q3 − Q1.
How to solve
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Example
The dot plot shows the number of goals scored for 9 matches. Each dot stands for one match. The same data as a list: S = [6, 6, 5, 4, 5, 0, 2, 9, 8]. What is the first quartile (Q1) of the data?
Answer: 3
Not quite. The answer is
💡 Read the dots from left to right to list the 9 values in order: 4, 5, 5, 6, 6, 6, 7, 9, 10. There is an odd number of values, so leave out the middle one (6) and split the rest. Lower half: 4, 5, 5, 6. Upper half: 6, 7, 9, 10. Q1 is halfway between the two middle numbers of the lower half: Q1 = (5 + 5) ÷ 2 = 5.
✓ Correct!
Not quite. The answer is
💡 Read the dots from left to right to list the 9 values in order: 4, 5, 5, 6, 6, 6, 7, 9, 10. There is an odd number of values, so leave out the middle one (6) and split the rest. Lower half: 4, 5, 5, 6. Upper half: 6, 7, 9, 10. Q1 is halfway between the two middle numbers of the lower half: Q1 = (5 + 5) ÷ 2 = 5.
💡 How to solve: Dot Plots: Quartiles and Interquartile Range
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Try a similar one
The dot plot shows the number of push-ups done in one minute for 9 students. Each dot stands for one student. The same data as a list: S = [25, 22, 27, 27, 20, 30, 26, 31, 23]. What is the first quartile (Q1) of the data?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Read the dots from left to right to list the 10 values in order: 0, 0, 0, 0, 3, 5, 5, 6, 7, 7. Split them into two equal halves. Lower half: 0, 0, 0, 0, 3. Upper half: 5, 5, 6, 7, 7. Q3 is the middle number of the upper half: Q3 = 6.
✓ Correct!
Not quite. The answer is
💡 Read the dots from left to right to list the 10 values in order: 0, 0, 0, 0, 3, 5, 5, 6, 7, 7. Split them into two equal halves. Lower half: 0, 0, 0, 0, 3. Upper half: 5, 5, 6, 7, 7. Q3 is the middle number of the upper half: Q3 = 6.
💡 How to solve: Dot Plots: Quartiles and Interquartile Range
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Try a similar one
The dot plot shows the high temperature in °C for 9 days. Each dot stands for one day. The same data as a list: S = [18, 16, 20, 18, 22, 20, 15, 25, 25]. What is the first quartile (Q1) of the data?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Read the dots from left to right to list the 9 values in order: 12, 13, 16, 18, 19, 21, 21, 22, 24. There is an odd number of values, so leave out the middle one (19) and split the rest. Lower half: 12, 13, 16, 18. Upper half: 21, 21, 22, 24. Q1 is halfway between the two middle numbers of the lower half: Q1 = (13 + 16) ÷ 2 = 14.5.
✓ Correct!
Not quite. The answer is
💡 Read the dots from left to right to list the 9 values in order: 12, 13, 16, 18, 19, 21, 21, 22, 24. There is an odd number of values, so leave out the middle one (19) and split the rest. Lower half: 12, 13, 16, 18. Upper half: 21, 21, 22, 24. Q1 is halfway between the two middle numbers of the lower half: Q1 = (13 + 16) ÷ 2 = 14.5.
💡 How to solve: Dot Plots: Quartiles and Interquartile Range
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Try a similar one
The dot plot shows the number of minutes the bus was late for 9 days. Each dot stands for one day. The same data as a list: S = [15, 9, 7, 13, 8, 5, 16, 5, 17]. What is the first quartile (Q1) of the data?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Read the dots from left to right to list the 10 values in order: 16, 16, 17, 19, 20, 20, 23, 25, 25, 27. Split them into two equal halves. Lower half: 16, 16, 17, 19, 20. Upper half: 20, 23, 25, 25, 27. Q3 is the middle number of the upper half: Q3 = 25.
✓ Correct!
Not quite. The answer is
💡 Read the dots from left to right to list the 10 values in order: 16, 16, 17, 19, 20, 20, 23, 25, 25, 27. Split them into two equal halves. Lower half: 16, 16, 17, 19, 20. Upper half: 20, 23, 25, 25, 27. Q3 is the middle number of the upper half: Q3 = 25.
💡 How to solve: Dot Plots: Quartiles and Interquartile Range
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Try a similar one
The dot plot shows the number of push-ups done in one minute for 9 students. Each dot stands for one student. The same data as a list: S = [17, 13, 16, 17, 17, 15, 14, 24, 22]. What is the first quartile (Q1) of the data?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Read the dots from left to right to list the 9 values in order: 22, 25, 26, 26, 26, 27, 29, 30, 30. There is an odd number of values, so leave out the middle one (26) and split the rest. Lower half: 22, 25, 26, 26. Upper half: 27, 29, 30, 30. Q1 is halfway between the two middle numbers of the lower half: Q1 = (25 + 26) ÷ 2 = 25.5.
✓ Correct!
Not quite. The answer is
💡 Read the dots from left to right to list the 9 values in order: 22, 25, 26, 26, 26, 27, 29, 30, 30. There is an odd number of values, so leave out the middle one (26) and split the rest. Lower half: 22, 25, 26, 26. Upper half: 27, 29, 30, 30. Q1 is halfway between the two middle numbers of the lower half: Q1 = (25 + 26) ÷ 2 = 25.5.
💡 How to solve: Dot Plots: Quartiles and Interquartile Range
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Try a similar one
The dot plot shows the number of points scored for 9 games. Each dot stands for one game. The same data as a list: S = [16, 10, 16, 8, 9, 10, 11, 12, 19]. What is the first quartile (Q1) of the data?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Read the dots from left to right to list the 10 values in order: 1, 1, 2, 4, 6, 6, 7, 11, 12, 13. Split them into two equal halves. Lower half: 1, 1, 2, 4, 6. Upper half: 6, 7, 11, 12, 13. Q3 is the middle number of the upper half: Q3 = 11.
✓ Correct!
Not quite. The answer is
💡 Read the dots from left to right to list the 10 values in order: 1, 1, 2, 4, 6, 6, 7, 11, 12, 13. Split them into two equal halves. Lower half: 1, 1, 2, 4, 6. Upper half: 6, 7, 11, 12, 13. Q3 is the middle number of the upper half: Q3 = 11.
💡 How to solve: Dot Plots: Quartiles and Interquartile Range
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Try a similar one
The dot plot shows the number of rainy days for 9 months. Each dot stands for one month. The same data as a list: S = [7, 9, 7, 12, 10, 13, 17, 7, 11]. What is the first quartile (Q1) of the data?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Read the dots from left to right to list the 9 values in order: 3, 4, 5, 5, 8, 9, 9, 11, 11. There is an odd number of values, so leave out the middle one (8) and split the rest. Lower half: 3, 4, 5, 5. Upper half: 9, 9, 11, 11. Q1 is halfway between the two middle numbers of the lower half: Q1 = (4 + 5) ÷ 2 = 4.5.
✓ Correct!
Not quite. The answer is
💡 Read the dots from left to right to list the 9 values in order: 3, 4, 5, 5, 8, 9, 9, 11, 11. There is an odd number of values, so leave out the middle one (8) and split the rest. Lower half: 3, 4, 5, 5. Upper half: 9, 9, 11, 11. Q1 is halfway between the two middle numbers of the lower half: Q1 = (4 + 5) ÷ 2 = 4.5.
💡 How to solve: Dot Plots: Quartiles and Interquartile Range
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Try a similar one
The dot plot shows the number of hours of sleep for 9 students. Each dot stands for one student. The same data as a list: S = [4, 11, 11, 12, 5, 8, 7, 5, 9]. What is the first quartile (Q1) of the data?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Read the dots from left to right to list the 10 values in order: 5, 8, 8, 10, 10, 11, 12, 12, 13, 14. Split them into two equal halves. Lower half: 5, 8, 8, 10, 10. Upper half: 11, 12, 12, 13, 14. Q3 is the middle number of the upper half: Q3 = 12.
✓ Correct!
Not quite. The answer is
💡 Read the dots from left to right to list the 10 values in order: 5, 8, 8, 10, 10, 11, 12, 12, 13, 14. Split them into two equal halves. Lower half: 5, 8, 8, 10, 10. Upper half: 11, 12, 12, 13, 14. Q3 is the middle number of the upper half: Q3 = 12.
💡 How to solve: Dot Plots: Quartiles and Interquartile Range
Count the dots from the left to split the data into a lower half and an upper half (with an odd number of values, the middle one belongs to neither half). Q1 is the median of the lower half, Q3 is the median of the upper half, and the interquartile range is IQR = Q3 − Q1, the spread of the middle half of the data. Example: S = [1, 2, 4, 5, 7, 8, 9, 12]. Lower half 1, 2, 4, 5 gives Q1 = 3; upper half 7, 8, 9, 12 gives Q3 = 8.5; IQR = 8.5 − 3 = 5.5.
Try a similar one
The dot plot shows the number of books read over the summer for 9 students. Each dot stands for one student. The same data as a list: S = [9, 4, 0, 12, 5, 7, 2, 5, 5]. What is the first quartile (Q1) of the data?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
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Dot Plots: Quartiles and Interquartile Range — Easy Worksheet 1
Q1 is the median of the lower half of the data and Q3 is the median of the upper half. When there is an odd number of values, leave the median out of both halves. IQR = Q3 − Q1.