Label each of the three following sentences that describe accuracy with an A. Label each sentence that describes precision with a P.
___P___5. Four of five repetitions of a measurement were named numerically identical, and the fifth varied from the others in value by less than 1%.
___A____6. Eight measurements were spread over a wide range.
___A____7. A single measurement is within 1% of the correct value.
I GUESS I would call the first one P but it depends, partly at least, on whether 1% is acceptable or not. Frankly, I don't think 1% is very good precision. (1% is 10 parts per thousand. I think of good as 1 part per thousand.) I am also troubled by the phrase "were named numerically equal". I don't know what that means.
For #6 I GUESS I would might call it accuracy although it really isn't because there is nothing to indicate how close these measurments were to the accepted value. Eight measurements spread over a wide range with nothing to indicate how far the average of these numbers are from the accepted value makes me think this is an example of VERY POOR precision.
7. I would choose accuracy.
To label each sentence correctly, let's understand the definitions of accuracy and precision:
Accuracy refers to how close a measurement is to the true or accepted value. It measures the systematic errors or biases in a measurement.
Precision, on the other hand, refers to how close the repeated measurements are to each other, regardless of their closeness to the true value. It measures the random errors in a measurement.
Now, let's analyze each sentence:
5. Four of the five repetitions of a measurement were named numerically identical, and the fifth varied from the others in value by less than 1%.
This sentence describes precision because it specifically mentions the closeness of the repetitions to each other within a certain percentage. The variation within 1% indicates a level of repeatability.
6. Eight measurements were spread over a wide range.
This sentence describes accuracy because it implies that the measurements cover a wide range, which suggests that they may not be close to the accepted value. Without further information, it is difficult to determine the level of accuracy.
7. A single measurement is within 1% of the correct value.
This sentence describes accuracy because it indicates that the measurement is within 1% of the correct value. It measures how close the measurement is to the actual value.
So, to label the sentences correctly:
5. P (Precision)
6. A (Accuracy)
7. A (Accuracy)