Variables:
A data frame with 60 observations on the following 5 variables.
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strength
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paste strength.
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batch
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delivery batch from which the sample was sample. A factor with 10 levels: ‘A’ to ‘J’.
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cask
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cask within the delivery batch from which the sample was chosen. A factor with 3 levels: ‘a’ to ‘c’.
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sample
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the sample of paste whose strength was assayed, two assays per sample. A factor with 30 levels: ‘A:a’ to ‘J:c’.
Details
The data are described in Davies and Goldsmith (1972) as coming from “ deliveries of a chemical paste product contained in casks where, in addition to sampling and testing errors, there are variations in quality between deliveries ... As a routine, three casks selected at random from each delivery were sampled and the samples were kept for reference. ... Ten of the delivery batches were sampled at random and two analytical tests carried out on each of the 30 samples”.