Benzene concentrations (ppb) at one background and one downgradient well (eight monthly measures at each well).
EPA.09.Ex.16.2.benzene.dfA data frame with 16 observations on the following 3 variables.
Montha factor indicating the month of collection
Well.typea factor indicating the well type (background vs. downgradient)
Benzene.ppba numeric vector of benzene concentrations (ppb)