Accuracy is how close a measured value is to the actual (true) value.
Precision is how close the measured values are to each other.
No, No, No.
Precision is how many significant digits there are. What is todays temp?
AnswerPrecise: 64.3421F
AnswerAccurate: 99F
Generally accepted as true: 98F
So which is more accurate, and which is more precise?
To understand accuracy and precision, let's first define a few terms:
1. Measured value: This refers to a value obtained through a measurement process. It could be the result of a physical measurement, a calculation, or any other quantitative assessment.
2. Actual value (True value): This is the real value of the quantity being measured. It is often considered as the ideal or perfect value, but it may not always be known or directly measurable. The actual value serves as a point of reference for evaluating the accuracy of the measured values.
Now, let's dive into accuracy and precision:
1. Accuracy: Accuracy refers to how close a measured value is to the actual (true) value of a quantity. Essentially, it represents the correctness or trueness of a measurement. If a measured value is accurate, it means that it is very close to the actual value. Conversely, if it is inaccurate, there is a significant difference between the measured and actual values.
To assess accuracy, you need to compare the measured value with the actual value. However, obtaining the actual value is not always feasible, so in practice, you often rely on accepted standard values, reference materials, or calibration procedures to estimate the actual value. By comparing the measured value with these references, you can determine how accurate the measurement is.
2. Precision: Precision, on the other hand, refers to the closeness or repeatability of the measured values to each other. In other words, it assesses the level of consistency in a series of measurements.
A measurement process with high precision produces measured values that are very close to each other, even if they might not be close to the actual value. Conversely, a measurement process with low precision generates measured values that are scattered or highly variable, regardless of their proximity to the actual value.
To evaluate precision, you can perform multiple measurements of the same quantity using the same measurement process. Then, check the variation or difference between these measured values. Statistical methods like standard deviation or coefficient of variation can quantify the precision of the measurements.
In summary, accuracy focuses on how close a measured value is to the actual value, while precision emphasizes the consistency or repeatability of measured values. Both accuracy and precision are important in obtaining reliable and meaningful measurements, but they evaluate different aspects of the measurement process.