1. Accuracy & Precision

2. All available digits + 1 estimated digit A. 87.5oC B. 13.0 mL
Notes sheet #1 and 2
All available digits + 1 estimated digit
A oC
B mL
C cm
The estimated digit is given in red.

3. Accuracy the agreement between experimental data and a known value.
Example: Which one is more accurate?
Before
After
Sand
20.00 g
19.59 g
Salt
3.21 g

4. Precision how well experimental values agree with each other
Example: Which data is most precise?
Before
After Group 1
After Group 2
After Group 3
Sand
20.00 g
19.59 g
15.98
9.26
Salt
10.21 g
10.23
10.19
Is it accurate?

5. Draw a target diagram that shows precision but not accuracy

6. Draw a target diagram that shows accuracy but not precision

7. Draw a target diagram that shows both accuracy and precision

8. #7
Each of five students used the same ruler to measure the length of the same pencil. These data resulted: cm, cm, cm, cm, and cm. The actual length of the pencil was cm. Describe whether accuracy and precision are each good or poor for these measurements.

9. A measurement was taken three times. The correct measurement was 68
A measurement was taken three times. The correct measurement was 68.1 mL. Circle whether the set of measurements is accurate, precise, both, or neither.
78.1 mL, 43.9 mL, 2 mL
accurate precise both neither
68.1 mL, 68.2 mL, 68.0 mL
98.0 mL, 98.2 mL, 97.9 mL
72.0 mL, 60.3 mL, 68.1 mL
accurate precise both neither

10. Accuracy and Precision Stations
Begin Station Review Activity

11. Accuracy and Precision Stations Summary—Station 1
Instrument
Separation of Markings in mL
Most accurate
Least accurate
Small graduated cylinder
0.5
Large graduated cylinder 1
Small beaker 10
Erlenmeyer Flask 25
Large beaker 50
Florence flask
No marks