Prep · Median, IQR, and measures of center

1. 1.

   Find the IQR of 8, 9, 10, 12, 14, 15, 17.

   Answer. 6

   Q1 = 9, Q3 = 15, IQR = 15 − 9 = 6.

2. 2.

   Find the IQR of 8, 9, 10, 12, 14, 15, 17.

   Answer. 6

   Q1 = 9, Q3 = 15, IQR = 15 − 9 = 6.

3. 3.

   Find the median of 5, 6, 7, 9, 11, 12, 14.

   Answer. 9

   Ordered already. Middle value is 9.

4. 4.

   Find the IQR of 9, 10, 11, 13, 15, 16, 18.

   Answer. 6

   Q1 = 10, Q3 = 16, IQR = 16 − 10 = 6.

5. 5.

   Find the median of 7, 8, 9, 11, 13, 14, 16. Then Jonah needs 5 of that amount. What is the total they need?

   Answer. 55

   Ordered already. Middle value is 11. Then multiply by 5: 55.

6. 6.

   Find the median of 4, 5, 6, 8, 10, 11, 13. Then Sam needs 2 of that amount. What is the total they need?

   Answer. 16

   Ordered already. Middle value is 8. Then multiply by 2: 16.

7. 7.

   Find the median of 9, 10, 11, 13, 15, 16, 18. Then Luis needs 3 of that amount. What is the total they need?

   Answer. 39

   Ordered already. Middle value is 13. Then multiply by 3: 39.

8. 8.

   Find the median of 4, 5, 6, 8, 10, 11, 13. Then Grace needs 3 of that amount. What is the total they need?

   Answer. 24

   Ordered already. Middle value is 8. Then multiply by 3: 24.

9. 9.

   Find the median of 4, 5, 6, 8, 10, 11, 13. Then Mei needs 3 of that amount. What is the total they need?

   Answer. 24

   Ordered already. Middle value is 8. Then multiply by 3: 24.

10. 10.

    Find the median of 9, 10, 11, 13, 15, 16, 18. Then Mei needs 2 of that amount. What is the total they need?

    Answer. 26

    Ordered already. Middle value is 13. Then multiply by 2: 26.

11. 11.

    Think

    Priya tried this problem:
    Find the IQR of 9, 10, 11, 13, 15, 16, 18.
    Priya wrote -6. That is not correct. What is the right answer?

    Answer. 6

    Priya’s answer -6 is off. Q1 = 10, Q3 = 16, IQR = 16 − 10 = 6.

12. 12.

    Think

    Mei tried this problem:
    Find the median of 10, 11, 12, 14, 16, 17, 19.
    Mei wrote 28. That is not correct. What is the right answer?

    Answer. 14

    Mei’s answer 28 is off. Ordered already. Middle value is 14.

Original extra practice. Keys are computed from the items, not guessed.