Nickel concentrations (ppb) from four wells (five observations per year for each well). The Guidance Document has the label “Year” instead of “Well”; corrected in Errata.
EPA.09.Ex.10.1.nickel.dfA data frame with 20 observations on the following 3 variables.
Montha numeric vector indicating the month the sample was taken
Wella factor indicating the well number
Nickel.ppba numeric vector of nickel concentrations (ppb)