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2012.20 CHOLINE MLT
LUJP087 ADVZ021
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:
Choline 2012-20 MLT
Study date:
2015-2106
Sample ID:
LUJP087&ADVZ021
1 Total number of laboratories
p
11
2 Total number of replicates
Sum(n(L))
22
3 Average number of replicates per lab
Sum(n(L))/p
2.00
4 Sum of replicates squared
Sum(n(L)^2)
44
5 Sum of lab totals
Sum(Lab Totals)
402.90
6 Sum of lab averages
Sum(Lab Avg.)
201.45
7 Sum of lab totals squared/n(L)
Sum(T(L)^2/n(L))
7515.70
8 Sum of squares for replicates
SSQ(devn.)
1.15
9 Sum of Squares for Labs
LSS
137.13
10 Effective mean number of reps per lab
NBAR
2.0000
11 Unweighted mean of the laboratory averages
XBAR
18.3136
12 Overall mean of all data (grand mean)
XBARBAR
18.3136
13 Repeatability variance
s(r)^2
0.1050
14 Repeatability standard deviation
s(r)
0.3240
15 "Pure" among laboratories variance
s(L)^2
6.8040
16 Reproducibility variance
s(R)^2
6.9090
17 Reproducibility standard deviation
s(R)
2.6285
18 Repeatability relative standard deviation
RSD(r)
1.77
19 Reproducibility relative standard deviation
RSD(R)
14.35
20 Repeatability value = 2.8*s(r)
r
0.907
21 Reproducibility value = 2.8*s(R)
R
7.360
22 HORRAT value
1.97
Record these values for Results
Number of Laboratories
11
Largest within variance
0.3200
Largest average lab result
23.3500
Smallest average lab result
15.0000
If proportion of labs removed from the total is less than 2/9, then
Cochran's Test =
27.7%
Critical value, 2.5% significance =
62.2%
Result =
Not significant
with maximum within lab variance for
Lab 11
If Cochran test is not significant, then proceed
Single Grubb's Test =
18.8%
Critical value, 2.5% significance =
38.8%
Result =
Not significant
highest average at
Lab 10
gives % decrease in standard deviation =
18.8%
lowest average at
Lab 5
gives % decrease in standard deviation =
4.3%
If Single Grubb's test is not significant, then proceed
Double Grubb's Test =
31.8%
Critical value, 2.5% significance =
52.1%
Result =
Not significant
Excluding the highest avg. and next highest avg
gives % decrease in standard deviation =
31.8%
Excluding the lowest avg. and next lowest avg
gives % decrease in standard deviation =
10.4%
Excluding the highest avg. and lowest avg
gives % decrease in standard deviation =
23.8%