Copper concentrations (ppb) at three background and two compliance wells
(eight monthly samples for each well; first four missing at compliance wells).
Nondetects reported as <5.
EPA.92c.copper2.dfA data frame with 40 observations on the following 6 variables.
Copper.origa character vector of original copper concentrations (ppb)
Coppera numeric vector of copper concentrations with <5 coded as 5
Censoreda logical vector indicating which observations are censored
Montha factor indicating the month of collection
Wella factor indicating the well number
Well.typea factor indicating the well type (background vs. compliance)