Chrysene concentrations (ppb) at two background wells and one compliance well (four monthly measures at each well).
EPA.09.Ex.18.2.chrysene.dfA data frame with 12 observations on the following 4 variables.
Montha factor indicating the month of collection
Wella factor indicating the well number
Well.typea factor indicating the well type (background vs. compliance)
Chrysene.ppba numeric vector of chrysene concentrations (ppb)