38 
Evaluation of the results 
The evaluation procedure has been conducted for 
nuclides with four or more results (K-40, Cs-134, 
Cs-137, Pb-210, Ra-226, Pu-239,240, and Am- 
241). 
The Z-score for an item indicates how far and in 
what direction the item deviates from the mean of 
its distribution, expressed in units of its distribution’s 
standard deviation. The Z-score value for an item is 
calculated according to: 
x t -x 
Z i=~ 
<J , 
where 
x = arithmetic mean of the values, 
<J- standard deviation of the values. 
Z-score of K-40 
Figure A12. 
Column diagram of 
Z-scores for K-40. 
3,00 
2,00 
1,00 
0,00 
-1,00 
-2,00 
-3,00 
,22 
0,46 
0,93 
n 
I F -0,08 
-0,26 
-2,08 
I I 
-0,15 
-0,05 
□ STUK/FI 
■ RISO/DK 
□ CLOR/PO 
□ LVEA/LV 
■ ERPC/ES 
□ DHIG/GE 
□ SSI/SW 
□ BFFG/GE 
Z-score of Cs-137 
Figure A13. 
Column diagram of 
Z-scores for Cs-137. 
□ STUK/FI 
■ RISO/DK 
□ CLOR/PO 
□ LVEA/LV 
■ ERPC/ES 
□ DHIG/GE 
□ SSI/SW 
□ BFFG/GE