Silver concentrations (mg/L) from an interlab comparison. There are 34 observations out of a total of 56 that are reported as <DL, where DL denotes a detection limit. There are 12 distinct detection limits.
A data frame with 56 observations on the following 4 variables.
a character vector of original silver concentrations (mg/L)
a numeric vector with nondetects coded to the detection limit
a logical vector indicating which observations are censored
the natural logarithm of
Helsel, D.R., and T.A. Cohn. (1988). Estimation of Descriptive Statistics for Multiply Censored Water Quality Data. Water Resources Research 24(12), 1997–2004.
Janzer, V.J. (1986). Report of the U.S. Geological Survey's Analytical Evaluation Program–Standard Reference Water Samples M6, M94, T95, N16, P8, and SED3. Technical Report, Branch of Quality Assurance, U.S. Geological Survey, Arvada, CO.