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o p e r a t i n g t h e a n a l y z e r
s
Proficiency
To analyze proficiency samples, select PROFICIENCY under
ANALYZE QC. These samples are analyzed without applying cor-
relation values to the measured results, which enables the EasyStat
results to be grouped together on the proficiency program’s interlabo-
ratory reports. The proficiency results are not stored.
Stored QC Information
Select STORED INFORMATION from the SECOND MENU,
then QC RESULTS to view the last quality control results, print QC
statistics or plot QC charts. PRINT QC STATS prints the results
by date, mean, standard deviation, and coefficient of variation for the
stored quality control results. PLOT QC CHARTS prints the stored
quality control results as a Levey-Jennings chart. The statistics are calcu-
lated according to the following definitions:
A minimum of 5 stored quality control results is required to
calculate statistics.
Definitions
Mean: The mean (x) is the value derived by dividing the sum (Σ)
of the observed values by the number of observations (n) stored in
memory (between 5 and 93 values).
SD: The standard deviation (SD) measures dispersion within the
distribution of data stored.
where: SD =
Σ(x-x)
2
=
sum of the square of each difference from the mean
n = number of observations
CV:
The coefficient of variation (CV) is a measure (as a percentage) of the
variation from the mean within the set of stored data.
_
x
=
Σ values
n
(x-x)
2
n-1
x
CV = 100 SD
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