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Make predictions with a line of best fit

8th grade (Year 9 in England) · 16 questions · Common Core: 8.SP.A.2, 8.SP.A.3 · England: KS3 Statistics, GCSE Foundation Statistics

Name

Date

Score/ 16

  1. Question 1

    Data was collected for x from 1 to 8, and the line of best fit is y = 2x + 9. Kofi uses it to predict y when x = 56. Why should Kofi be careful?

    xy12345678910481216202428320y = 2x + 9(1, 11)(2, 11)(3, 17)(4, 18)(5, 21)(6, 20)(7, 23)(8, 27)
    • A. x is far outside the data range, so the trend may not continue
    • B. The answer will be a decimal
    • C. Lines of best fit can never be used
    • D. The line has a positive slope

  2. Question 2

    A line of best fit is y = 1x + 4. For which x does it predict y = 12?

    Answer

  3. Question 3

    The line of best fit for test score (y) against hours of practice (x) is y = 7x + 39. Predict the score after 2 hours.

    Answer

  4. Question 4

    Data was collected for x from 1 to 8, and the line of best fit is y = 4x + 19. Mei uses it to predict y when x = 43. Why should Mei be careful?

    xy1234567891028560y = 4x + 19(1, 22)(2, 28)(3, 31)(4, 37)(5, 40)(6, 45)(7, 48)(8, 49)
    • A. Lines of best fit can never be used
    • B. x is far outside the data range, so the trend may not continue
    • C. The answer will be a decimal
    • D. The line has a positive slope

  5. Question 5

    A line of best fit is y = 1.5x + 6. For which x does it predict y = 18?

    Answer

  6. Question 6

    The line of best fit for test score (y) against hours of practice (x) is y = 4x + 50. Predict the score after 9 hours.

    Answer

  7. Question 7

    Data was collected for x from 1 to 8, and the line of best fit is y = 3x + 7. Arjun uses it to predict y when x = 52. Why should Arjun be careful?

    xy1234567891015300y = 3x + 7(1, 12)(2, 13)(3, 15)(4, 21)(5, 21)(6, 27)(7, 26)(8, 29)
    • A. x is far outside the data range, so the trend may not continue
    • B. The answer will be a decimal
    • C. The line has a positive slope
    • D. Lines of best fit can never be used

  8. Question 8

    A line of best fit is y = 1x + 9. For which x does it predict y = 16?

    Answer

  9. Question 9

    The line of best fit for test score (y) against hours of practice (x) is y = 4x + 34. Predict the score after 8 hours.

    Answer

  10. Question 10

    Data was collected for x from 1 to 8, and the line of best fit is y = 4x + 8. Ana uses it to predict y when x = 33. Why should Ana be careful?

    xy123456789106121824303642480y = 4x + 8(1, 11)(2, 17)(3, 18)(4, 26)(5, 30)(6, 31)(7, 38)(8, 42)
    • A. x is far outside the data range, so the trend may not continue
    • B. The answer will be a decimal
    • C. The line has a positive slope
    • D. Lines of best fit can never be used

  11. Question 11

    A line of best fit is y = 1x + 6. For which x does it predict y = 13?

    Answer

  12. Question 12

    The line of best fit for test score (y) against hours of practice (x) is y = 8x + 45. Predict the score after 3 hours.

    Answer

  13. Question 13

    Data was collected for x from 1 to 8, and the line of best fit is y = 4x + 10. Omar uses it to predict y when x = 51. Why should Omar be careful?

    xy12345678910612182430364248540y = 4x + 10(1, 15)(2, 18)(3, 24)(4, 26)(5, 30)(6, 35)(7, 39)(8, 42)
    • A. The answer will be a decimal
    • B. Lines of best fit can never be used
    • C. The line has a positive slope
    • D. x is far outside the data range, so the trend may not continue

  14. Question 14

    A line of best fit is y = 1.5x + 2. For which x does it predict y = 18.5?

    Answer

  15. Question 15

    The line of best fit for test score (y) against hours of practice (x) is y = 7x + 28. Predict the score after 9 hours.

    Answer

  16. Question 16

    Data was collected for x from 1 to 8, and the line of best fit is y = 4x + 5. Ben uses it to predict y when x = 59. Why should Ben be careful?

    xy123456789101530450y = 4x + 5(1, 7)(2, 11)(3, 19)(4, 22)(5, 26)(6, 29)(7, 32)(8, 37)
    • A. Lines of best fit can never be used
    • B. The answer will be a decimal
    • C. x is far outside the data range, so the trend may not continue
    • D. The line has a positive slope

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  1. x is far outside the data range, so the trend may not continue
  2. 8
  3. 53
  4. x is far outside the data range, so the trend may not continue
  5. 8
  6. 86
  7. x is far outside the data range, so the trend may not continue
  8. 7
  9. 66
  10. x is far outside the data range, so the trend may not continue
  11. 7
  12. 69
  13. x is far outside the data range, so the trend may not continue
  14. 11
  15. 91
  16. x is far outside the data range, so the trend may not continue