TABLE 6.

Uncertainties about the reproducibility of the gravimetric analysis and the stoichiometry of weighing forms.

Run no.	Purity of original La2O3 by oxide form, %	Purity of original La2O3 by sulfate form, %	Mean of the purity values a , %	Absolute difference of the purity values b , %	$\left|\text{Dif}.\right|/\sqrt{3}$ , %
1	99.976 ± 0.003	99.947 ± 0.008	99.961	0.030	0.017
2	100.052 ±0.009	99.978 ± 0.006	100.015	0.074	0.043
3	99.973 ± 0.005	100.049 ± 0.007	100.011	0.075	0.043
4	99.938 ± 0.003	99.948 ± 0.008	99.943	0.010	0.0058
5	99.972 ± 0.005	99.963 ± 0.006	99.967	0.0085	0.0049
6	99.977 ± 0.006	99.965 ± 0.013	99.971	0.012	0.0069
7	99.995 ± 0.005	99.942 ± 0.007	99.968	0.053	0.030
8	100.014 ± 0.011	99.974 ± 0.006	99.994	0.040	0.023
9	99.934 ±0.006	99.962 ± 0.006	99.948	0.029	0.016
10	99.990 ± 0.005	100.001 ± 0.008	99.996	0.012	0.0069
		Mean	99.977	Root mean square	0.024 c
		RSD	0.025
		$\text{RSD}/\sqrt{n}$	0.0080 d

^aMean of the purity values obtained in the two weighing forms.

^bAbsolute difference in purity values obtained from two weighing forms.

^cThe root mean square was used as uncertainty for the stoichiometry of weighing forms.

^dThe $\text{RSD}/\sqrt{n}$ was used as uncertainty of the reproducibility of the gravimetric analysis.