pH measurements in a chemical process
A data frame with 35 observations on the following 2 variables.
a factor with levels
a numeric vector
For each of three batches of material numerous pH readings were taken over the course of the production process. For this material the pH should be consistent throughout production.
Peter R. Nelson, Marie Coffin and Karen A. F. Copeland (2003), Introductory Statistics for Engineering Experimentation, Elsevier. (Appendix A)
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