Table 5.

Statistical test for drinking water radioactivity comparison before and after the operation of SNPP.

Type of Water	Gross α (Mean ±SD, Bq/L)		Z	P	Gross β (Mean ±SD, Bq/L)		Z	P
	Before (2014–2017)	After (2018–2021)			Before (2014–2017)	After (2018–2021)
Raw water	0.011 ± 0.007	0.009 ± 0.005	−1.137	0.255	0.048 ± 0.016a	0.047 ± 0.016	−0.683	0.495
Factory water	0.009 ± 0.003	0.008 ± 0.000	−1.225	0.221	0.055 ± 0.022	0.044 ± 0.014	−1.740	0.082
Tap water	0.009 ± 0.003	0.008 ± 0.002	−0.329	0.742	0.040 ± 0.014a	0.039 ± 0.010	−0.680	0.497

^aSome discrete values are eliminated according to Grubbs criterion.