Precision and Accuracy (1.3.2) Flashcards
• Any measurement will have a degree of uncertainty.
• Any measurement will have a degree of uncertainty.
• Precision is the reproducibility of a measurement of a given quantity.
• Precision is the reproducibility of a measurement of a given quantity.
• Accuracy is how close a measurement is to the true value.
• Accuracy is how close a measurement is to the true value.
Any measurement will have a degree of uncertainty.
For example, a measurement of 166 pounds could actually be anywhere from 165 pounds to 167 pounds. This is often written as 166 ± 1 pound.
Furthermore, if the scale isn’t calibrated correctly, the value of 166 pounds might not be correct.
Any measurement will have a degree of uncertainty.
For example, a measurement of 166 pounds could actually be anywhere from 165 pounds to 167 pounds. This is often written as 166 ± 1 pound.
Furthermore, if the scale isn’t calibrated correctly, the value of 166 pounds might not be correct.
Precision is the reproducibility of a measurement of a given quantity. Precision reflects the uncertainty in the last digit of a measurement.
Whenever a measurement is made, the last digit of the
measurement must be estimated to one digit past the marking on the measuring device. This estimation leads to random error. Measurements with higher precision have less random error.
For example, if the black bar is measured with a ruler marked in centimeters, the length is somewhere between 0 cm and 1 cm, but the tenths digit must be estimated. If the black bar is measured with a ruler marked in millimeters, the length is somewhere between 0.6 cm and 0.7 cm. In this case, the hundredths digit can be estimated, and the value is more precise.
Precision is the reproducibility of a measurement of a given quantity. Precision reflects the uncertainty in the last digit of a measurement.
Whenever a measurement is made, the last digit of the
measurement must be estimated to one digit past the marking on the measuring device. This estimation leads to random error. Measurements with higher precision have less random error.
For example, if the black bar is measured with a ruler marked in centimeters, the length is somewhere between 0 cm and 1 cm, but the tenths digit must be estimated. If the black bar is measured with a ruler marked in millimeters, the length is somewhere between 0.6 cm and 0.7 cm. In this case, the hundredths digit can be estimated, and the value is more precise.
Accuracy is how close a measurement is to the true value. An analogy for this is a game of darts. The target is analogous to the true value. If three darts are thrown in a close grouping, but are nowhere near the target, they are precise, but not accurate.
Accuracy is how close a measurement is to the true value. An analogy for this is a game of darts. The target is analogous to the true value. If three darts are thrown in a close grouping, but are nowhere near the target, they are precise, but not accurate.
Systematic Error
An error inherent to the measurement of a value.
