Accuracy & Precision

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. 87.5oC B. 13.0 mL C. 4.15 cm The estimated digit is given in red.

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

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?

Draw a target diagram that shows precision but not accuracy

Draw a target diagram that shows accuracy but not precision

Draw a target diagram that shows both accuracy and precision

#7 Each of five students used the same ruler to measure the length of the same pencil. These data resulted: 15.33 cm, 15.34 cm, 15.33 cm, 15.33 cm, and 15.34 cm. The actual length of the pencil was 15.85 cm. Describe whether accuracy and precision are each good or poor for these measurements.

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

Accuracy and Precision Stations Begin Station Review Activity

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