Between-bottle homogeneity test of new certified reference materials employing wavelength dispersive X-ray fluorescence spectrometry

Table 3 Descriptive statistics of elements contents (weight%) in KACST402 CRM

Element	Average	SD	RSD%	RAD%	Skewness	Kurtosis
Al	6.153	0.0450	0.73	0.61	− 0.20	− 1.86
Ba	0.051	0.0019	3.70	2.78	0.82	0.28
Ca	4.047	0.0382	0.94	0.77	0.84	− 1.29
Cl	0.592	0.0085	1.44	1.20	− 0.26	− 1.57
Cr	0.018	0.0011	6.22	5.55	0.36	− 2.32
Cu	0.009	0.0007	8.09	6.39	0.40	− 0.80
Fe	5.406	0.0223	0.41	0.33	0.63	− 1.04
K	1.424	0.0960	6.74	4.31	2.50	6.41
Mg	1.860	0.0100	0.54	0.46	0.00	− 2.60
Mn	0.088	0.0016	1.84	1.46	0.77	− 1.26
Na	1.160	0.0082	0.70	0.49	0.00	− 1.20
Ni	0.013	0.0001	0.73	0.58	− 0.28	0.04
P	0.079	0.0144	18.3	12.2	− 2.11	4.69
Pb	0.012	0.0009	7.47	4.78	2.22	5.27
Rb	0.004	0.0002	4.78	3.90	− 0.29	− 1.45
S	0.328	0.0050	1.53	1.21	0.70	− 0.06
Si	19.61	0.1574	0.80	0.67	0.04	− 1.68
Sr	0.041	0.0002	0.57	0.40	1.84	3.68
Ti	0.473	0.0088	1.86	1.42	0.93	− 0.11
Zn	0.344	0.0031	0.90	0.81	0.28	− 2.47
Zr	0.027	0.0001	0.50	0.38	− 0.35	− 0.30

SD standard deviation, RSD relative standard deviation, RAD relative average deviation