374-375 / 620
Table 2
T
stat
p
-value
684.8
97.2%
Value is listed as
"informational"
only
Determined by
NIST
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
Accuracy - Analytical bias compared to reference material
Certified Reference Material
Measured Results
CRM Product
Analyte
Certified value Uncertainty Certified range Concentration
Difference from
certified value
Bias
Confidence interval
NIST 1849a
Chloride
N/A
N/A
710 mg/100g
using instrumental
neutron activation
analysis (INAA)
2.059
0.064
#NUM!
-
#NUM!
n
/
sd
d
d
d
n
t
crit
sd
n
t
crit
sd
crit
t
SPIFAN ERP Checklist v1.0
Chlor-02 MEF Form
FOR ERP USE ONLY
DO NOT DISTRIBUTE