Nickel concentrations (ppb) from four wells (five observations per year for each well). The Guidance Document has the label “Year” instead of “Well”; corrected in Errata.
A data frame with 20 observations on the following 3 variables.
a numeric vector indicating the month the sample was taken
a factor indicating the well number
a numeric vector of nickel concentrations (ppb)
USEPA. (2009). Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities, Unified Guidance. EPA 530/R-09-007, March 2009. Office of Resource Conservation and Recovery, Program Implementation and Information Division. U.S. Environmental Protection Agency, Washington, D.C., p.10-12.
USEPA. (2010). Errata Sheet - March 2009 Unified Guidance. EPA 530/R-09-007a, August 9, 2010. Office of Resource Conservation and Recovery, Program Information and Implementation Division. U.S. Environmental Protection Agency, Washington, D.C.