AS 2706:2003 pdf free download.Numerical values- Rounding and interpretation of limiting values.
2.3 ROUNDING INTERVAL The rounding interval is the smallest possible difference (excluding zero) between two rounded values in the same series. Example 11: If a value is rounded to the nearest unit in the second decimal place, the rounding interval is 0.01. If a value is rounded to two units in the second decimal place, the rounding interval is 0.02. If a value is rounded to five units in the sccond decimal place, the rounding interval is 0.05. 2.4 ACCURACY OF AN INSTRUMENT Accuracy is a qualitative term describing the degree of closeness with which the indications of an instrument approach the true values of the measurand. NOTE: The quantitative expression of this concept should be in terms of uncertainty. 2.5 UNCERTAINTY OF MEASUREMENT Uncertainty is a parameter, associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand. NOTES: The paramctcr may bc, for cxamplc, a standard deviation (or a givcn multiple of it), or the half-width of an interval having a stated level of confidence. 2 Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated from the statistical distribution of the results of series of measurements and can be characterized by experimental standard deviations. The other components，which can also be characterized by standard deviations, are evaluated from assumed probability distributions based on experience or other information.
3.1 GENERAL CONSIDERATIONS 3.1.1 Principle Rounding a number (sometimes called rounding off) consists in the rejection of any figures beyond the number of significant figures which it is desired to retain and, if necessary, in the light of the rejected figures, the adjustment of the last figure or figures retained. The unrounded value should embody all the useful information that can be extracted from the data or the computation on which it is based. 3.1.2 Number of figures to be retained A necessary preliminary to the rounding of a given number is a decision on the appropriate number of figures to be retained (see Section 4). 3.1.3 Direction of rounding The direction of rounding is evident unless the unrounded number falls exactly midway between two successive round values in which case a rounding rule is required to provide consistency of procedure (see Clause 3.2 and Clause 3.3). 3.1.4 Rounding interval In most instances, the rounding will be required to the nearest unit in the last place retained. n some cases, this may be too fine to be justifiable, whereas rounding to one significant figure less would be too coarse. It may then be desirable to round to two units or five units in the last place of figures. Whenever practicable, the rounding of values should be taken to the nearest unit in the last place retained. If values are rounded to two units or five units, the rounding interval should be stated.AS 2706 pdf download.