136 / 696
Table 3
Accuracy - Analytical bias compared to reference material
SRM Product
Code
Analyte
Reference
value
1
Measured value
Bias
(mg/kg pwd)
Conc. (mg/kg pwd)
T
stat
p
-value Confidence Interval
1.969
2.067
2.081
2.023
2.047
-
1.971
2.013
1.987
1.995
T
stat
=
where: = mean of the differences between measured results and reference value
sd = standard deviation of the differences between results and reference value
n
= number of replicate analyses of SRM
H
0
: = 0, The null hypothesis is that there is no difference between the measured results and the certified value:
p
-value: is the probability (at the 95% levels of confidence) of obtaining the test statistic assuming that the null hypothesis is true.
p
-value < 0.05 indicate a difference of statistical signifance between measured results and SRM.
95% confidence interval: The true population of the measured value expected to fall within the confidence interval estimate 95% of the time.
lower limit = mean
-
upper limit = mean +
where: = critical values of the t-distribution
sd = standard deviation of the differences between results an reference value
n
= number of replicate analyses of SRM
0.08234797 1.9856
2.0484
1849a
CLC-10b
Biotin
1.99
1.985
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Bio-03 (February 2016)
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