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

234.0 220.5 230.1 222.5 236.4 235.6 235.2 244.4 210.1 210.6 220.6 224.8

-30.3 -16.8 -26.4 -18.8 -32.7 -31.9 -31.5 -40.7

SRM 1849a

Riboflavin (ug/100g)

203.7

5.2

198.5 - 208.9

23.4

7.579

0.000

220.3 - 233.9

-6.4 -6.9

-16.9 -21.1

Mean

227.1

-23.4

SD

10.7

10.7

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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