Calculating the mean · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Calculating the mean

Mathematics · Data & Statistics · ages 10-11
Name ______________________   Date ____________

  1. Lena took five quizzes and scored 62, 95, 70, 88 and 80. What is her mean quiz score?

    Answer: ______________

  2. What do you do first when calculating the mean of a group of numbers?

    • Add all the values together
    • Multiply all the values together
    • Pick out the largest value

  3. The mean of a data set always matches at least one of the individual values.

    Circle one:   True   False

  4. Find the mean of 2, 6, and 4.

    A2B6C4
    • 4
    • 6
    • 12

  5. The mean of three numbers is 7. Two of the numbers are 2 and 8. What is the third number?

    Answer: ______________

  6. Zoe read 12, 9, 15 and 8 pages on four nights. What is the mean number of pages she read each night?

    Answer: ______________

  7. A library lent out books for 5 days. The mean was 30 books a day. On four of the days it lent 26, 34, 31 and 27 books. How many books did it lend on the fifth day?

    Answer: ______________

  8. Find the mean of these five test scores: 72, 85, 90, 68, and 95.

    Score 172Score 285Score 390Score 468Score 595

    Answer: ______________

  9. Priya adds 8, 10, and 12 to get 30, then divides by 2 to get a mean of 15. What is her mistake?

    • She should have subtracted the numbers instead of adding them
    • She should divide by 3, since there are 3 numbers, not 2
    • She should divide 30 by 30 instead of 2

  10. The mean score for 6 games is 9. The first five games scored 7, 8, 10, 9, and 11. What was the score in the sixth game?

    Answer: ______________

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Answer key

For grown-ups. Fold this page away before handing over the rest.

Calculating the mean W1-mt_Cg8VPguS_V-s1

  1. 79 · Add all five scores to get 395, then divide by 5. The mean score is 79.
  2. Add all the values together · Finding the mean always starts with adding every value in the data set.
  3. False · The mean of 1 and 5 is 3: (1 + 5) ÷ 2 = 3. Neither value is 3, so the mean does not always match an individual value.
  4. 4 · Add the three numbers: 2+6+4=12. Then divide by 3: 12÷3=4.
  5. 11 · Three numbers with mean 7 must add up to 21. Since 2+8=10, the missing number is 21-10=11.
  6. 11 · Add the pages to get 44, then divide by the 4 nights: 44 divided by 4 = 11.
  7. 32 · Five days with a mean of 30 make 150 books. The four known days add to 118, so the fifth day was 150 - 118 = 32.
  8. 82 · Add all five scores to get 410, then divide by 5: 410÷5=82.
  9. She should divide by 3, since there are 3 numbers, not 2 · You divide the total by how many numbers you added. There were 3 numbers, so the answer should be 30÷3=10.
  10. 9 · Six scores with mean 9 total 54. The first five add up to 45, so the sixth score is 54-45=9.
Worksheet · LightMySky