PLTW EngineeringActivity 3.8 Precision and Accuracy ofMeasurementIntroductionThis concept of random and systematic errors is related to the precision and accuracyof measurements. Precision characterizes the system's probability of providing thesame result every time a sample is measured (related to random error). Accuracycharacterizes the system's ability to provide a mean close to the true value when asample is measured many times (related to systematic error). We can determine theprecision of a measurement instrument by making repeated measurements of the samesample and calculating the standard deviation of those measurements. However, wewill not be able to correct any single measurement due to a low precision instrument.Simply stated, the effects of random uncertainties can be reduced by repeatedmeasurement, but it is not possible to correct for random errors.We can determine the accuracy of a measurement instrument by comparing theexperimental mean of a large number of measurements of a sample for which we knowthe "true value" of the characteristic of the sample. A sample for which we know the"true value" would be our calibration standard. We may also need to characterize theaccuracy of the measurement instrument by observing historical trends in thedistribution of measured values for the calibration standard (this allows for determiningthe systematic error expected from environmental effects, etc.). The effects ofsystematic uncertainties cannot be reduced by repeated measurements. The cause ofsystematic errors may be known or unknown. If both the cause and the value of asystematic error are known, it can be corrected for by "subtracting" the known deviation.However, there will still remain a systematic uncertainty component associated with thiscorrection.Equipment• Engineering notebook• Gauge blockDial caliper

Accuracy and precision are crucial concepts in science, and their definitions are frequently…

This concept of random and systematic errors is related to the precision and accuracy of measurements. Precision characterizes the system's probability of providing the same result every time a sample is measured (related to random error). Accuracy characterizes the system's ability to provide a mean close to the true value when a sample is measured many times (related to systematic error). We can determine the precision of a measurement instrument by making repeated measurements of the same sample and calculating the standard deviation of those measurements. However, we will not be able to correct any single measurement due to a low precision instrument. Simply stated, the effects of random uncertainties can be reduced by repeated measurement, but it is not possible to correct for random errors.

This concept of random and systematic errors is related to the precision and accuracy of measurements. Precision characterizes the system's probability of providing the same result every time a sample is measured (related to random error). Accuracy characterizes the system's ability to provide a mean close to the true value when a sample is measured many times (related to systematic error). We can determine the precision of a measurement instrument by making repeated measurements of the same sample and calculating the standard deviation of those measurements. However, we will not be able to correct any single measurement due to a low precision instrument. Simply stated, the effects of random uncertainties can be reduced by repeated measurement, but it is not possible to correct for random errors.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.23P: Using the information in Problem 1.22, estimate the ambient air temperature that could cause...

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