618-619 / 670
Table 2
Nominal
T
stat
p
-value
1.18
0.1
1.21
0.0
1.16
0.1
1.17
0.1
1.19
0.0
1.13
0.1
1.16
0.1
1.16
0.1
1.17
0.1
Mean
1.2
0.1
SD
0.0
0.0
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
0.000
1.2
-0.1
Uncertainty Certified range Concentration
Difference from
certified value
Confidence interval
- 1.2
0.19
1.04 - 1.42
7.969
S
RM 1849a
V
itamin D3
1.23
Bias
Accuracy - Analytical bias compared to reference material
Certified Reference Material
Measured Results
CRM product
Analyte
Certified value
n
/
sd
d
d
d
n
t
crit
sd
n
t
crit
sd
crit
t
SPIFAN ERP Checklist v1.0
VitD-17 MEF (February 2016)
FOR ERP USE ONLY
DO NOT DISTRIBUTE