Mercury level in employee urine samples
Mercury level in employee urine samples
A data frame with 12 observations on the following 5 variables.
month
an ordered factor with levels from
January
to December
person1
mercury concentration in person 1's urine
person2
mercury concentration in person 2's urine
person3
mercury concentration in person 3's urine
person4
mercury concentration in person 4's urine
Employees who work in a high risk area of a chemical plant are monitored monthly for mercury exposure.
Peter R. Nelson, Marie Coffin and Karen A. F. Copeland (2003), Introductory Statistics for Engineering Experimentation, Elsevier. (Appendix A)
str(urine) dotplot(month ~ person1 + person2 + person3 + person4, urine, outer = FALSE, type = c("p","l"), auto.key = list(columns = 2, lines = TRUE, points = FALSE), xlab = "Mercury level in urine")
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