Zinc concentrations (ppb) at five background wells
(eight samples for each well). Nondetects reported as <7.
EPA.92c.zinc.dfA data frame with 40 observations on the following 5 variables.
Zinc.origa character vector of original zinc concentrations (ppb)
Zinca numeric vector of zinc concentrations with <7 coded as 7
Censoreda logical vector indicating which observations are censored
Samplea factor indicating the sample number
Wella factor indicating the well number