1. Day 62 – Precision and Accuracy

2. Accuracy: Precision: Vocabulary 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

3. 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)

4. Accuracy without Precision Accuracy & Precision
No Precision & No Accuracy
Precision without Accuracy

5. 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

6. Example: Precision
Who is more precise when measuring the same 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

7. Explain the difference between the accuracy and precision
Give examples of accuracy and precision

8. Evaluate whether the following are precise, accurate or both.
High Accuracy
High Precision
Low Accuracy
Low Precision
Low Accuracy
High Precision

9. Reading a Meterstick First digit (known) = 2 2.?? cm
Second digit (known) = ? cm
Third digit (estimated) between cm
Length reported = cm
or cm
or cm

10. 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

11. Learning Check What is the length of the line? 1) 9.31 cm 2) 9.32 cm
How does your answer compare with your neighbor’s answer? Why or why not?