Sulfate concentrations (ppm) at one background well and one downgradient well (eight quarterly measures at each well).
EPA.09.Ex.16.1.sulfate.dfA data frame with 16 observations on the following 4 variables.
Montha factor indicating the month of collection
Yeara factor indicating the year of collection
Well.typea factor indicating the well type (background vs. downgradient)
Sulfate.ppma numeric vector of sulfate concentrations (ppm)