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Table 2

Nominal

T

stat

p

-value

105.0

3.1

110.5

-2.5

103.3

4.7

106.5

1.5

106.6

1.4

108.5

-0.5

102.4

5.6

107.9

0.1

108.5

-0.5

Mean

106.6

1.4

SD

2.6

2.6

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

SRM1849a

Nicotinamide

108

10

98 - 118

Certified range

104.6 - 108.6

Bias

Confidence interval

-1.4

1.632

0.141

Accuracy - Analytical bias compared to reference material

Certified Reference Material

Measured Results

CRM product

Analyte

Certified value Uncertainty

Concentration

Difference from

certified value

n

/

sd

d

d

d

n

t

crit

sd

n

t

crit

sd

crit

t

SPIFAN ERP Checklist v1.0

BVit-01 - MEF FORM

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