Arsenic concentrations (ppb) at three background wells and one compliance well
(six monthly samples for each well; first four missing at compliance well). Nondetects
reported as <5.
EPA.92c.arsenic2.dfA data frame with 24 observations on the following 6 variables.
Arsenic.origa character vector of original arsenic concentrations (ppb)
Arsenica numeric vector of arsenic 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)