DAY 62 PRECISION AND ACCURACY VOCABULARY Accuracy How

DAY 62 – PRECISION AND ACCURACY

VOCABULARY Accuracy: � How close you are to the actual value � Depends on the person measuring � Calculated by the formula: Precision: � How finely tuned your measurements are or how close they can be to each other � Depends on the measuring tool � Determined by the number of significant digits

Accuracy & Precision may be demonstrated by shooting at a target. Accuracy is represented by hitting the bulls eye (the accepted value) Precision is represented by a tight grouping of shots (they are finely tuned)

Accuracy & Precision without Accuracy without Precision No Precision & No Accuracy

EXAMPLE: ACCURACY Who is more accurate when measuring a book that has a true length of 17. 0 cm? Susan: 17. 0 cm, 16. 0 cm, 18. 0 cm, 15. 0 cm Amy: 15. 5 cm, 15. 0 cm, 15. 2 cm, 15. 3 cm

EXAMPLE: PRECISION Who is more precise when measuring the same 17. 0 cm book? Susan: 17. 0 cm, 16. 0 cm, 18. 0 cm, 15. 0 cm Amy: 15. 5 cm, 15. 0 cm, 15. 2 cm, 15. 3 cm

1. Explain the difference between the accuracy and precision 2. Give examples of accuracy and precision

EVALUATE WHETHER THE FOLLOWING ARE PRECISE, ACCURATE OR BOTH. Low Accuracy Low Precision High Accuracy High Precision

READING A METERSTICK First digit (known) = 2 2. ? ? cm Second digit (known) = 0. 7 2. 7? cm Third digit (estimated) between 0. 05 - 0. 08 cm Length reported 2. 77 cm = or 2. 76 cm or 2. 78 cm

KNOWN + ESTIMATED DIGITS In 2. 77 cm… • Known digits 2 and 7 are 100% certain • The third digit 7 is estimated (uncertain) • In the reported length, all three digits (2. 77 cm) are significant including the estimated one

LEARNING CHECK What is the length of the line? 1) 9. 31 cm 2) 9. 32 cm 3) 9. 33 cm How does your answer compare with your neighbor’s answer? Why or why not?