SPIFAN Nutrients ERP Book_9-29-15

BVit-02 - MEF FORM FOR ERP USE ONLY DO NOT DISTRIBUTE

Table 2

Accuracy - Analytical bias compared to reference material Certified Reference Material

Measured Results

T stat Bias

Difference from certified value

CRM product

Analyte

Certified value Uncertainty Certified range Concentration

Confidence interval

p -value

Nominal

125.6 128.5 128.7 128.8 130.3 130.0 131.2 136.4 122.5 122.4 127.4 130.2

0.1

-2.8 -3.0 -3.1 -4.6 -4.3 -5.5

SRM 1849a

Thiamin (ug/100g)

125.7

9.8

115.9 - 135.5

2.8

2.545

0.027

126.1

- 130.9

-10.7

3.2 3.3

-1.7 -4.5

Mean

128.5

-2.8

SD

3.8

3.8

d

=

T stat

/ sd

n

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 d

H 0 : = 0, The null hypothesis is that there is no difference between the measured results and the certified value: d

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.

sd

sd

t crit

t crit

lower limit = mean -

upper limit = mean +

n

n

t

where: = critical values of the t-distribution

crit

sd = standard deviation of the differences between results an reference value n = number of replicate analyses of SRM

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