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.df
A data frame with 24 observations on the following 6 variables.
Arsenic.orig
a character vector of original arsenic concentrations (ppb)
Arsenic
a numeric vector of arsenic concentrations with <5
coded as 5
Censored
a logical vector indicating which observations are censored
Month
a factor indicating the month of collection
Well
a factor indicating the well number
Well.type
a factor indicating the well type (background vs. compliance)