1. Accuracy vs. Precision

2. 2 minutes: Write what you think accuracy and precision mean 1 minute: discuss at your table what you think

3. Definitions: Accuracy and precision are used in context of measurement. Accuracy is the degree of conformity of a measured or calculated quantity to its actual (true) value, while precision is the degree to which further measurements or calculations show the same or similar results. In other words, the precision of an experiment/object/value is a measure of the reliability of the experiment, or how reproducible the experiment is. The accuracy of an experiment/object/value is a measure of how closely the experimental results agree with a true or accepted value.

4. 1 minute: Do you need to refine your definitions?

5. Chart Comparison: Accuracy Precision Definition The degree of closeness to true value. The degree to which an instrument or process will repeat the same value. Measurements Single factor or measurement Multiple measurements or factors are needed About A term used in measuring a process or device. Uses Physics, chemistry, engineering, statistics and so on.

6. Examples: A stopped clock will be accurate twice in day, but it will not be precise - a reflection on its quality. If a clock reflects the right time in 10 readings at 10 different points in time it can be considered precise and therefore of high quality. So, if you are playing soccer and you always hit the left goal post instead of scoring, then you are not accurate, but you are precise!

7. More Info: Another difference between the two is that accuracy can be determined by one measurement while many measurements are needed to determine precision.

8. In other words…. Accuracy Accuracy is how close a measured value is to the actual (true) value. Precision Precision is how close the measured values are to each other

9. Fill in the three targets on your paper

10. How would you classify these? Low Accuracy High Precision High Accuracy High Precision High Accuracy Low Precision

11. Do your targets match the ones on the previous slide?