urine {EngrExpt}

Mercury level in employee urine samples

Description

Mercury level in employee urine samples

Format

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

Details

Employees who work in a high risk area of a chemical plant are monitored monthly for mercury exposure.

References

Peter R. Nelson, Marie Coffin and Karen A. F. Copeland (2003), Introductory Statistics for Engineering Experimentation, Elsevier. (Appendix A)

Examples

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")