Accuracy, precision and percent error

Answer Key - Grade 10 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Three trials of salt's density give 2.12, 2.2 and 2.16 g/cm³. The accepted value is 2.17 g/cm³. What is the percent error of the mean, to 0.01%, Ari?

   0.46 %
2. 2.

   Three trials of sugar's density give 1.6, 1.62 and 1.55 g/cm³. The accepted value is 1.5805 g/cm³. What is the percent error of the mean, to 0.01%, Bo?

   0.6 %
3. 3.

   Three trials of water's density give 1.003, 0.995 and 1.002 g/cm³. The accepted value is 0.99802 g/cm³. What is the percent error of the mean, to 0.01%, Esme?

   0.2 %
4. 4.

   A balance that isn't zeroed causes which kind of error, Jun?

   • No error
   • Random
   • Systematic
5. 5.

   Readings of a thermometer wobble a little up and down each time. Which kind of error is that, Kira?

   • Systematic
   • Random
   • A calculation slip
6. 6.

   Why doesn't averaging more trials fix a systematic error, Luz?

   • Averages make errors bigger each time
   • Systematic errors are random
   • Every trial is shifted the same way
7. 7.

   Milo says Group 2's results must be right because they agree so closely. Agree or disagree?

   • Disagree: they miss 2.17
   • Agree: close results are correct
   • Agree: agreement shows accuracy
8. 8.

   Noah says precise results are always accurate. Agree or disagree?

   • Agree: tight groups hit the center
   • Disagree: they can all be off
   • Agree: precision means accuracy
9. 9.

   Pia says percent error can be found without an accepted value. Agree or disagree?

   • Agree: the trials are enough
   • Disagree: it needs one
   • Agree: use the biggest trial
10. 10.

    One trial has a 0.1% error. What does that show about precision, Zee?

    • Nothing yet: precision needs repeats
    • It is very precise, as one trial shows
    • It is not precise