# 2015.14 Vitamin B (July 2018)

2015.14 (JULY 2018) BVit-02 AOAC_Edit_Niacin_Tot_MLT- AOAC_BlindDup_00729RF00

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AOAC International Interlaboratory Study Workbook

Version:

2.1

Blind (Unpaired) Replicates Results Sheet Seq.

Item

Symbol

Value

Study name: Study date: Sample ID:

AOAC 2015.14 Simultaneous Determination of Total Vitamins B1, B2

7/24/2018

00729RF00 - DYLB360/ZMQM883

1 Total number of laboratories 2 Total number of replicates 4 Sum of replicates squared 5 Sum of lab totals 6 Sum of lab averages 7 Sum of lab totals squared/n(L) 8 Sum of squares for replicates 9 Sum of Squares for Labs 3 Average number of replicates per lab

p

8

Sum(n(L)) Sum(n(L))/p Sum(n(L)^2)

16

2.00

32

Sum(Lab Totals) Sum(Lab Avg.) Sum(T(L)^2/n(L))

66.69 33.34 278.69

SSQ(devn.)

0.02 0.73

LSS

10 Effective mean number of reps per lab 11 Unweighted mean of the laboratory averages 12 Overall mean of all data (grand mean) 14 Repeatability standard deviation 15 "Pure" among laboratories variance 17 Reproducibility standard deviation 18 Repeatability relative standard deviation 19 Reproducibility relative standard deviation 16 Reproducibility variance 13 Repeatability variance

NBAR XBAR

2.0000 4.1680 4.1680 0.0028 0.0528 0.0510 0.0538 0.2320 1.27 5.57 0.148 0.650

XBARBAR

s(r)^2

s(r)

s(L)^2 s(R)^2

s(R)

RSD(r) RSD(R)

20 Repeatability value = 2.8*s(r) 21 Reproducibility value = 2.8*s(R)

r

R

0.22

22 HORRAT value

Record these values for Results Number of Laboratories Largest within variance Largest average lab result Smallest average lab result

8

0.0102 4.4915 3.8005

If proportion of labs removed from the total is less than 2/9, then Cochran's Test =

45.7% 73.6%

Critical value, 2.5% significance =

Result =

Not significant

with maximum within lab variance for

Lab 9

If Cochran test is not significant, then proceed

17.8% 50.6%

Single Grubb's Test =

Critical value, 2.5% significance =

Result =

Not significant

highest average at

Lab 7

gives % decrease in standard deviation =

11.3%

lowest average at

Lab 8

gives % decrease in standard deviation =

17.8%

If Single Grubb's test is not significant, then proceed Double Grubb's Test =

30.7% 66.0%

Critical value, 2.5% significance =

Result =

Not significant

Excluding the highest avg. and next highest avg gives % decrease in standard deviation = Excluding the lowest avg. and next lowest avg gives % decrease in standard deviation = Excluding the highest avg. and lowest avg gives % decrease in standard deviation =

16.6%

30.7%

30.4%

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