When reporting expanded uncertainty, rounding the number of significant figures can affect the associated level of confidence. A simple numerical method is used to measure the level of confidence obtained after different rounding methods have been applied. This also offers some insight into the meaning of level of confidence. The findings are consistent with NIST recommendations that, for a level of confidence of 95 %, an expanded uncertainty should be rounded to two significant figures and the accompanying measured value reported in the same precision.

中文翻译：

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四舍五入扩大的不确定性

在报告扩大的不确定性时，四舍五入有效数字的数量会影响相关的置信水平。使用一种简单的数值方法来衡量在应用不同的舍入方法后获得的置信水平。这也提供了对置信水平含义的一些见解。结果与 NIST 建议一致，即对于 95% 的置信水平，扩展不确定度应四舍五入为两位有效数字，并以相同的精度报告随附的测量值。