OMB Meeting Book - January 8, 2015

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EXAMPLE

Consider the March subset of ‘AOAC-C01-Fat-Data.csv’. There are two replicates for each collaborator, and the average of these is the results analyzed for reproducibility effects. Repeatability is measured by the difference in replicate pairs. It will be assumed for purposes of illustration that all collaborators all used the same test method for fat. There are 42 collaborators, with average results ranging from 13.08 to 36.08 percent fat, with median and mean results 14.42 and 15.10. Using method 2), the repeatability standard deviation s r is 0.4739, the apparent intercollaborator standard deviation s is 3.503, and the repeatability adjusted value for reproducibility standard deviation is 3.519. The boxplot and normal Q-Q plot for these data are: 15 20 25 30 35 March 15 20 25 30 35 March SampleQuantiles

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Theoretical Quantiles

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Recommended to OMB by Committee on Statistics: 07-17-2013 Reviewed and approved by OMB: 07-18-2013