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Accuracy is also used as a statistical measure of how well a binary classification test correctly identifies or excludes a condition. That is, the accuracy is the proportion of correct predictions (both true positives and true negatives) among the total number of cases examined. [10] As such, it compares estimates of pre- and post-test probability.
Class 0.5 is an ANSI C12.20 accuracy class for electric meters with absolute accuracy better than ± 0.5% of the nominal full scale reading. [1] Typically, a class specifies accuracy at a number of points, with the absolute accuracy at lower values being better than the nominal "percentage of full scale" accuracy.
In electrical engineering, characteristics like current or voltage can be measured by an ammeter, a voltmeter, a multimeter, etc.The ammeter is used in series with the load, so the same current flows through the load and the ammeter.
A national measurement system (NMS) is a network of laboratories, calibration facilities and accreditation bodies which implement and maintain a country's measurement infrastructure. [8] [9] The NMS sets measurement standards, ensuring the accuracy, consistency, comparability, and reliability of measurements made in the country. [57]
The formal definition of calibration by the International Bureau of Weights and Measures (BIPM) is the following: "Operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties (of the calibrated instrument or ...
There are different definitions within laboratory quality control, wherein "analytical sensitivity" is defined as the smallest amount of substance in a sample that can accurately be measured by an assay (synonymously to detection limit), and "analytical specificity" is defined as the ability of an assay to measure one particular organism or ...
For accuracy the volume on graduated cylinders is depicted on scales with 3 significant digits: 100mL cylinders have 1ml grading divisions while 10mL cylinders have 0.1 mL grading divisions. Two classes of accuracy exist for graduated cylinders. Class A has double the accuracy of class B. [4] Cylinders can have single or double scales. Single ...
The accuracy of micrometers is checked by using them to measure gauge blocks, [17] rods, or similar standards whose lengths are precisely and accurately known. If the gauge block is known to be 0.75000 ± 0.00005 inch ("seven-fifty plus or minus fifty millionths", that is, "seven hundred fifty thou plus or minus half a tenth"), then the ...