Mercury concentrations (ppb) at four background and two compliance wells.
EPA.09.Ex.19.5.mercury.dfA data frame with 36 observations on the following 6 variables.
Eventa factor indicating the time of collection
Wella factor indicating the well number
Well.typea factor indicating the well type (background vs. compliance)
Mercury.ppb.origa character vector of original mercury concentrations (ppb)
Mercury.ppba numeric vector of mercury concentrations (ppb) with nondetects set to their detection limit
Censoreda logical vector indicating which observations are censored