Certificate Air
calibration certificate of air flow meter states +/- 5%of full scale.how to calculate uncertainty?
*Suppose following are the flow readings:
Reading 1 : 100.00
Reading 2 : 100.50
Reading 3 : 95.00
Reading 4 : 95.00
Here the avarage flow is 100.
Range is +/-5% on a full scale of 100.
Standard deviation=3.0375954
*Measurement of Uncertainty:A set of possible states or outcomes where probabilities are assigned to each possible state or outcome - this also includes the application of a probability density function to continuous variables .
*The uncertainty of a measurement is stated by giving a range of values which are likely to enclose the true value. This may be denoted by error bars on a graph, or as value ± uncertainty, or as decimal fraction(uncertainty).
*Often, the uncertainty of a measurement is found by repeating the measurement enough times to get a good estimate of the standard deviation of the values. Then, any single value has an uncertainty equal to the standard deviation. However, if the values are averaged, then the mean measurement value has a much smaller uncertainty, equal to the standard error of the mean, which is the standard deviation divided by the square root of the number of measurements.
*Precision indicates how close together or how repeatable the results are. A precise measuring instrument will give very nearly the same result each time it is used.
There are several ways to report the precision of results. The simplest is the range (the difference between the highest and lowest results) often reported as a deviation from the average.
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