Agilent Technologies 7500 ICP-MS - Averaging Repetition Files

A-28
Agilent 7500 ICP-MS ChemStation Operator’s Manual
Appendix
Averaging Repetition Files
When the repetition data files are averaged to create an average results file, the
following formulas are used:
where
x
avg
: average count of the averaged results file
s
avg
: standard deviation of the averaged results file
n
i
: repetition number of the individual repetition file
x
i
: average count of the individual repetition file
s
i
: standard deviation of the individual repetition file
x
avg
n
i
x
i
i
∑
n
i
i
∑
----------------=
s
avg
n
i
x
2
x
i
∑
⎝⎠
⎜⎟
⎛⎞
2
–
i
∑
i
∑
n
i
n
i
1–
i
∑
⎝⎠
⎜⎟
⎛⎞
i
∑
-----------------------------------------------=
x
i
∑
n
i
x
i
i
∑
=
x
2
i
∑
n
i
n
i
1–()s
i
2
n
i
x
i
()
2
+
n
i
--------------------------------------------------
i
∑
=