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?

   • Systematic
   • No error
   • Random
5. 5.

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

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

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

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

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

   • Agree: the trials are enough
   • Agree: use the biggest trial
   • Disagree: it needs one
8. 8.

   Lab A has a 0.5% error and Lab B a 4% error for the same value. Which is more accurate, Ren?

   • Neither can be judged
   • Lab B
   • Lab A
9. 9.

   What does a percent error of 0% mean, Tala?

   • No trials were done
   • The trials were each very different from it
   • The result matched the accepted value
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