2015.14 Vitamin B (July 2018)

2015.14 (JULY 2018) BVit-02 AOAC_Niacin_Tot_MLT- AOAC_BlindDup_00795RF

FOR ERP USE ONLY DO NOT DISTRIBUTE

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

00795RF - ECHL425/UOPM297

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

10 20

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

2.00

40

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

258.50 129.25 3366.19 0.34 24.95 2.0000 12.9252 12.9252 0.0338 0.1837 1.3694 1.4032 1.1846

SSQ(devn.)

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

XBARBAR

s(r)^2

s(r)

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

s(R)

1.42 9.16 0.514 3.317

RSD(r) RSD(R)

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

r

R

0.42

22 HORRAT value

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

10

0.0848 14.0640 9.8162

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

25.1% 65.5%

Critical value, 2.5% significance =

Result =

Not significant

with maximum within lab variance for

Lab 10

If Cochran test is not significant, then proceed

60.4% 42.0%

Single Grubb's Test =

Critical value, 2.5% significance =

Significant!

Result =

highest average at

Lab 3

gives % decrease in standard deviation =

0.2%

lowest average at

Lab 2

gives % decrease in standard deviation =

60.4%

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

67.4% 56.1%

Critical value, 2.5% significance =

Significant!

Result =

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 =

-1.4%

63.2%

67.4%