Efficient estimation of interlaboratory and in-house reproducibility standard deviation in factorial validation studies

2018 ◽  
Vol 13 (3) ◽  
pp. 315-322
Author(s):  
Steffen Uhlig ◽  
Petra Gowik
Keyword(s):  
Standard Deviation ◽  
Validation Studies ◽  
Efficient Estimation ◽  
Reproducibility Standard Deviation

scholarly journals Determining a One-Tailed Upper Limit for Future Sample Relative Reproducibility Standard Deviations

2006 ◽  
Vol 89 (3) ◽  
pp. 797-803
Author(s):  
Foster D McClure ◽  
Jung K Lee
Keyword(s):  
Standard Deviation ◽  
Linear Combination ◽  
Square Root ◽  
Sample Mean ◽  
Upper Limit ◽  
Reproducibility Standard Deviation ◽  
The Future ◽  
Standard Deviations ◽  
Future Sample

Abstract A formula was developed to determine a one-tailed 100p% upper limit for future sample percent relative reproducibility standard deviations <inline-formula> <inline-graphic href="inline_eq1.gif"/> </inline-formula> , where sR is the sample reproducibility standard deviation, which is the square root of a linear combination of the sample repeatability variance ( <inline-formula> <inline-graphic href="inline_eq2.gif"/> </inline-formula> ) plus the sample laboratory-to-laboratory variance ( <inline-formula> <inline-graphic href="inline_eq3.gif"/> </inline-formula> ), i.e., <inline-formula> <inline-graphic href="inline_eq4.gif"/> </inline-formula> , and y is the sample mean. The future RSDR, % is expected to arise from a population of potential RSDR, % values whose true mean is <inline-formula> <inline-graphic href="inline_eq5.gif"/> </inline-formula> , where R and are the population reproducibility standard deviation and mean, respectively.

Mass Loss on Drying for Instant Coffee: Collaborative Study

1980 ◽  
Vol 63 (2) ◽  
pp. 178-179
Author(s):  
William P Clinton ◽  
Paul H Manni ◽  
John M Ferry
Keyword(s):  
Standard Deviation ◽  
Mass Loss ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Instant Coffee ◽  
Reproducibility Standard Deviation ◽  
Repeatability Standard Deviation ◽  
Working Method

Abstract A collaborative study was undertaken to define an acceptable routine working method for determination of mass loss in instant coffee. Fourteen laboratories of 24 invited to participate submitted results. The repeatability standard deviation and coefficient of variation were 0.026 and 0.7%, respectively. The reproducibility standard deviation and coefficient of variation were 0.153 and 3.8%, respectively. The method has been adopted as official first action.

Microdiffusion and Fluoride-Specific Electrode Determination of Fluoride in Infant Foods: Collaborative Study

1981 ◽  
Vol 64 (4) ◽  
pp. 1021-1026
Author(s):  
Robert W Dabeka ◽  
Arthur D Mckenzie ◽  
◽  
R A Baetz ◽  
D W Bingham ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Variance Analysis ◽  
Infant Foods ◽  
Reproducibility Standard Deviation ◽  
Coefficients Of Variation ◽  
Repeatability Standard Deviation

Abstract Twelve laboratories analyzed (1 replicate) 12 samples of infant foods – milk, pears, and peas – containing 0.2-5 ppm F. There was one laboratory outlier. Mean coefficients of variation were 7.06% for intralaboratory determination of 3 sets of blind duplicates and 21.6% for interlaboratory determination of 12 samples. Variance analysis for all samples yielded a reproducibility standard deviation of 0.41 ppm; for 3 sets of blind duplicates, repeatability standard deviation was 0.26 ppm and reproducibility standard deviation was 0.32 ppm.

scholarly journals Liquid Chromatographic Determination of Maleic Hydrazide in Technical and Formulated Products: Collaborative Study

2006 ◽  
Vol 89 (4) ◽  
pp. 929-936 ◽  
Author(s):  
James L Mertz ◽  
Dora Y Lau ◽  
David M Borth ◽  
E D Ausan ◽  
O Bennett ◽  
...  
Keyword(s):  
Data Analysis ◽  
Standard Deviation ◽  
Potassium Salt ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Laboratory Data ◽  
Internal Standard ◽  
Reversed Phase ◽  
Reproducibility Standard Deviation ◽  
Repeatability Standard Deviation

Abstract Fourteen collaborating laboratories assayed maleic hydrazide (MH), 6-hydroxypyridazin-3(2H)-one, in technical and formulated products by reversed-phase liquid chromatography (LC) with sulfanilic acid as an internal standard. The active MH in the samples (6 lots) ranged from 16% (expressed as the potassium salt) to 98% (MH in the technical). A small amount of 1 M KOH was added to the technical MH and analytical standards to create the potassium salt of the analyte which is soluble in water. Test samples and standards were extracted with water containing the internal standard before analysis by LC on a C8 column with an ion-pairing eluting solution and UV detection at 254 nm. The concentration of MH was calculated by comparing the peak area response ratios of the analyte and the internal standard with those in the analytical standard solution. Eleven laboratories weighed each test sample twice with single analysis. Three laboratories weighed each sample once and made duplicate injections on the LC system. The data were analyzed using the 11 laboratories' results. A second data analysis was done including all laboratory results using a Youden pair approach, selecting one of 2 duplicate assay values randomly for each laboratory and sample. In the first data analysis, the repeatability standard deviation ranged from 0.07 to 1.39%; reproducibility standard deviation ranged from 0.22 to 1.39%. In the second data analysis (using all laboratory data), repeatability standard deviation ranged from 0.09 to 0.86%; reproducibility standard deviation ranged from 0.22 to 1.31%.

scholarly journals Sequential risk-efficient estimation of the parameter in the uniform density

2000 ◽  
Vol 23 (6) ◽  
pp. 415-423
Author(s):  
Z. Govindarajulu
Keyword(s):  
Standard Deviation ◽  
Asymptotic Properties ◽  
Stopping Time ◽  
Efficient Estimation ◽  
Sequential Procedure ◽  
Uniform Density ◽  
Expected Stopping Time ◽  
Explicit Expressions

We develop a risk-efficient sequential procedure for estimating the parameterθof the uniform density on(0,θ). We give explicit expressions for the distribution of the stopping time and derive its expectation and variance. We also tabulate the values of the expected stopping time and its standard deviation for some selected values of the parameter. Asymptotic properties such as efficiency and risk-efficiency are established.

Extractable Color of Capsicums and Oleoresin Paprika

1977 ◽  
Vol 60 (1) ◽  
pp. 1-4 ◽  
Author(s):  
James E Woodbury
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Trade Association ◽  
Reproducibility Standard Deviation ◽  
Glass Filter ◽  
Aoac Method ◽  
Standard Deviations ◽  
Color Value ◽  
Spice Trade

Abstract A collaborative study of the method for extractable color in capsicums and oleoresin paprika was conducted to determine if the NBS neutral glass filter standard is superior to the chemical standard now used as a spectrophotometer check. For a 1000 ASTA (American Spice Trade Association) color value sample, the reproducibility standard deviation was 49 with the chemical standard compared with 14 with the NBS filter. The repeatability standard deviations were 9.0 and 8.9, respectively. For a 2000 ASTA color value sample, the reproducibility standard deviation was 162 with the chemical standard compared with 44 with the NBS filter. The repeatability standard deviations were 12.9 and 10.1, respectively. The study also indicated that 16 hr in acetone extracted 8.0% more of a capsicum than the 4 hr in the present AOAC method. The repeatability standard deviations for 4 hr vs. 16 hr were 2.1 and 1.6. The method has been adopted as official first action.

The ‘Horwitz ratio’—a study of the ratio between reproducibility and repeatability precisions in the analysis of foodstuffs

2015 ◽  
Vol 7 (1) ◽  
pp. 375-379 ◽  
Author(s):  
Michael Thompson ◽  
Roger Wood
Keyword(s):  
Standard Deviation ◽  
Detection Capability ◽  
Reproducibility Standard Deviation ◽  
Repeatability Standard Deviation

In the analysis of food, the ratio of reproducibility standard deviation to repeatability standard deviation is usually close to 2.0. This has implications in estimating uncertainty and detection capability.

scholarly journals Determination of Selenium in Feeds and Premixes: Collaborative Study

1997 ◽  
Vol 80 (3) ◽  
pp. 469-480 ◽  
Author(s):  
Ivan S Palmer ◽  
Nancy Thiex ◽  
R Allen ◽  
E Alley ◽  
N Anderson ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Standard Deviation ◽  
Atomic Absorption ◽  
Collaborative Study ◽  
Hydride Generation ◽  
Poor Agreement ◽  
Reproducibility Standard Deviation ◽  
Repeatability Standard Deviation ◽  
Fluorometric Study

Abstract A total of 17 laboratories participated in a collaborative study for the determination of selenium in feeds and premixes using either a fluorometric or a continuous hydride generation atomic absorption (HGAA) method. Each collaborator analyzed 16 blind duplicate samples of feed and premixes from various feed manufacturers. The amount of Se in these materials ranged from 0.2 to 5500 μg/g. Six laboratories used only the fluorometric procedure, 8 laboratories used only the hydride generation atomic absorption procedure, and 3 laboratories used both procedures. One laboratory in the fluorometric study and 3 laboratories in the HGAA study were initially excluded because of invalid data. Poor agreement between the blind duplicates indicated probable sample interchange and/or dilution error. The data from 8 laboratories were submitted to statistical analysis, including data from 2 laboratories participating in both studies. The repeatability standard deviation (RSDr) for samples analyzed by the fluorometric procedure ranged from 5.9 to 33%, and the reproducibility standard deviation (RSDR) ranged from 12 to 33%. RSDf for samples analyzed by HGAA ranged from 2.8 to 18%, and RSDR ranged from 4.0 to 36%. Both fluorometric and continuous hydride generation atomic absorption methods for the determination of Se in feeds and premixes have been adopted first action by AOAC INTERNATIONAL.

scholarly journals Fructans in Foods and Food Products, Ion-Exchange Chromatographic Method: Collaborative Study

1997 ◽  
Vol 80 (5) ◽  
pp. 1029-1039 ◽  
Author(s):  
Hubert Hoebregs ◽  
P Balis ◽  
J De Vries ◽  
J v Eekelen ◽  
P Farnell ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Ion Exchange ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Food Products ◽  
Food Samples ◽  
Exchange Chromatography ◽  
Reproducibility Standard Deviation ◽  
Repeatability Standard Deviation

Abstract Nine collaborating laboratories assayed 6 blind duplicate pairs of food samples containing the fructans inulin or oligofructose. The 6 sample pairs ranged from low (4%) to high levels (40%). Following the proposed method, the samples were treated with amyloglucosidase and inulinase enzymes and the released sugars were determined byion exchange chromatography. Repeatability standard deviation ranged from 2.9 to 5.8%; reproducibility standard deviation ranged from 4.7 to 11.1%. The ion-exchange chromatographic method for determinationof fructans in food and food products has been adopted first action by AOAC INTERNATIONAL (997.08)

Cylinder Plate Assay for Determining Bacitracin in Premix Feeds and Finished Feeds: Collaborative Study

1982 ◽  
Vol 65 (5) ◽  
pp. 1168-1177
Author(s):  
John B Gallagher ◽  
Linda L Knotts ◽  
◽  
D Brennecke ◽  
H H Bryant ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Reverse Phase ◽  
Average Recovery ◽  
Plate Assay ◽  
The Poor ◽  
Reproducibility Standard Deviation ◽  
Assay Procedure ◽  
Acceptable Method ◽  
Repeatability Standard Deviation

Abstract A cylinder plate assay procedure was studied by 10 laboratories. For premix feeds, 3 samples of bacitracin methylene disalicylic acid and 3 samples of bacitracin zinc premixes covering the range of 10 to 50 g/lb were used. The repeatability standard deviation was 2.11, and the reproducibility standard deviation was 2.13. The average recovery of bacitracin was 101.5%. The method has been adopted official first action. For finished feeds, 6 samples of bacitracin methylene disalicylic acid and 6 samples of bacitracin zinc covering the range of 10 to 800 g/ton were used in the study. The procedure included a sample cleanup step using disposable reverse phase columns. This step appears to be the cause of the poor results reported by most collaborators. Continued study is needed to develop an acceptable method for finished feeds.

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