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2012.20 CHOLINE MLT
YKLP059 ZNPI092 - Remove Labs 9-10-11
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:
2015-2016
Sample ID:
YKLP059&ZNPI092
1 Total number of laboratories
p
8
2 Total number of replicates
Sum(n(L))
16
3 Average number of replicates per lab
Sum(n(L))/p
2.00
4 Sum of replicates squared
Sum(n(L)^2)
32
5 Sum of lab totals
Sum(Lab Totals)
262.10
6 Sum of lab averages
Sum(Lab Avg.)
131.05
7 Sum of lab totals squared/n(L)
Sum(T(L)^2/n(L))
4302.32
8 Sum of squares for replicates
SSQ(devn.)
0.33
9 Sum of Squares for Labs
LSS
8.79
10 Effective mean number of reps per lab
NBAR
2.0000
11 Unweighted mean of the laboratory averages
XBAR
16.3813
12 Overall mean of all data (grand mean)
XBARBAR
16.3813
13 Repeatability variance
s(r)^2
0.0419
14 Repeatability standard deviation
s(r)
0.2046
15 "Pure" among laboratories variance
s(L)^2
0.6069
16 Reproducibility variance
s(R)^2
0.6488
17 Reproducibility standard deviation
s(R)
0.8055
18 Repeatability relative standard deviation
RSD(r)
1.25
19 Reproducibility relative standard deviation
RSD(R)
4.92
20 Repeatability value = 2.8*s(r)
r
0.573
21 Reproducibility value = 2.8*s(R)
R
2.255
22 HORRAT value
0.66
Record these values for Results
Number of Laboratories
8
Largest within variance
0.0800
Largest average lab result
17.3000
Smallest average lab result
15.0500
If proportion of labs removed from the total is less than 2/9, then
Cochran's Test =
23.9%
Critical value, 2.5% significance =
73.6%
Result =
Not significant
with maximum within lab variance for
Lab 2
If Cochran test is not significant, then proceed
Single Grubb's Test =
20.7%
Critical value, 2.5% significance =
50.6%
Result =
Not significant
highest average at
Lab 2
gives % decrease in standard deviation =
4.6%
lowest average at
Lab 5
gives % decrease in standard deviation =
20.7%
If Single Grubb's test is not significant, then proceed
Double Grubb's Test =
27.0%
Critical value, 2.5% significance =
66.0%
Result =
Not significant
Excluding the highest avg. and next highest avg
gives % decrease in standard deviation =
13.0%
Excluding the lowest avg. and next lowest avg
gives % decrease in standard deviation =
27.0%
Excluding the highest avg. and lowest avg
gives % decrease in standard deviation =
25.3%