原文由 reagentlife(reagentlife) 发表:
我们有个客户购买了我们某个品牌的锑(Sb)ICP-MS 标准溶液,对应批号的浓度描述为1000+/-20.1 mg/L,不确定为扩展不确定度为20.1mg/L,相对不确定度为2.01%,客户觉得这个相对不确定度太高了,我想问下大家,从统计学的角度考虑,相对不确定度在多少范围内是合理的?2.01%是否超标了?
the uncertainty associated with the certified concentration is the expanded uncertainty at 95% CI with k=2. This
expanded uncertainty incorporates contributions from manufacturing, homogeneity, and stability.
不知道如何向客户解释了,我也在问老外,有答案我挂出来大家一起把下关啊![]()
ps:如果有理论文字描述就好了!
下面是国外的回复,国外从2012年4月份开始根据ISO guide 34的更新后的不确定度公式来计算不确定度,通过修正上述批号的数据为
1000+/-7.25 mg/L。
The assessment of uncertainty under ISO34 is somewhat complicated and includes elements of uncertainty associated with homogeneity and stability. Last month we implemented a new procedure for calculating uncertainty that has been approved by our ISO34 accrediting company. The new procedure minimizes the value . I will revise the reference certificate to reflect the new procedure. The expanded uncertainty is similar t o our other products.