Measurement random error

This indicates that to know the measurement random error it is not sufficient to know its magnitude only (confidence interval of measurement error) but also the significance level that facilitates the confidence estimate of the obtained measurements. Using the error mean square as a measurement accuracy property is convenient because that value in a normal distribution is associated with a confidence or confidence coefficient of 0.68 probability. The doubled error mean square 2S has... 

If bothy and x are subject to measurable random errors, one can derive parameters starting from the following equation to obtain a/ first ... 

Systematic errors result from sources traced to the methodology, the instrument, or the operator. These affect both the accuracy and the precision of the measurement. Random errors affect the precision and are difficult to eliminate as they result from random fluctuations in the measured signal because of noise and other factors. The imprecision of the entire procedure is often dominated by the random errors of the most imprecise step. The difference between an accurate and a precise method is illustrated in Fig. 3. 

Error in measurement is unavoidable. Again, characteristics of error fall into categories. Random error is fundamental to any measurement. Random error may make the measurement either too high or too low and is associated with the limitations of the equipment with which the measurement is made. Systematic error makes measurements consistently either too high or too low. This type of error is often associated with the existence of some unknown bias in the measurement apparatus. Impurities in metals provide one example of possible error sources. Suppose that an aluminum alloy contains very small amounts of another... 

Random error, also called indeterminate error, arises from limitations on our ability to make physical measurements and on natural fluctuations in the quantity being measured. Random error has an equal chance of being positive or negative. It is always present and cannot be corrected. One random error is that associated with reading a scale. Different people reading the scale in Figure 3-1 report a range of... 

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