Artel PCS 2, Procedure Manual

Page: 59 / 68

15A3356O
APPENDIX C
FORMULAS USED TO CALCULATE GROUP STATISTICS
Mean
n
x
x
n
i
i



1
Standard Deviation
 
1
1
2





n
x x
STD
n
i
i
Coefficient of Variation
% 100
 
x
STD
CV
Inaccuracy
 
100
volume nominal
volume nominal



x
INACC
Combined Expanded
Uncertainty of the mean,
k =2
 







  
n
STD
x
u
i
U
2
2
2
Standard Relative Uncertainties for PCS
Ranges 1 through 6:
u
1
=0.5%
u
4
=0.3%
u
2
=0.4%
u
5
=0.3%
u
3
=0.3%
u
6
=0.3%
(n is the number of data points)