Definitions For Reproducibility; Sample Mean M; Sample Standard Deviation S - Agilent Technologies 8453 Operator's Manual

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Evaluating System Suitability

Definitions for Reproducibility

Definitions for Reproducibility

For the statistical review of analytical data in terms of reproducibility the
sequence is considered as a small random sample taken out of an infinite
number of possible experimental results. To accomplish a complete set of
results, an unlimited amount of sample material as well as time would be
required. Strictly statistical data does only apply to a complete self-contained
set or population of data. Therefore a prerequisite for such a treatment is that
the selected sample can be assumed as representative for all data.

Sample Mean M

The mean value M of a random sample consisting of N measurements is
calculated from this limited set of N single observed values X
consecutive counter i according to the formula:
where:
N = number of discrete observations
X

Sample Standard Deviation S

Consider a random sample of size N. The sample standard deviation S for the
selected finite sample taken out of the large population of data is determined
by
250
= value of discrete observations indexed by i
i
i
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indexed with a