2015.14 Vitamin B (July 2018)

2015.14 (JULY 2018) BVit‐02 Total Bs ERP Evaluation Form

FOR ERP USE ONLY DO NOT DISTRIBUTE

Accuracy ‐ Analytical bias compared to reference material Certified Reference Material

Table 2

Measured Results

T stat Bias

Confidence interval 

CRM product

Analyte

Certified value Uncertainty Certified range Concentration Difference from  certified value

p ‐value

Nominal

234.0 220.5 230.1 222.5 236.4 235.6 235.2 244.4 210.1 210.6 220.6 224.8 227.1

‐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 ‐23.4 10.7

Mean   

SD   

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

crit t

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