cenCompareCdfs function

Comparison of empirical cdf of censored data

Plots the empirical cdf and cdfs of three theoretical distributions, fit by maximum likelihood estimation (MLE).

cenCompareCdfs(x.var, cens.var, dist3 = "norm", Yname = yname)

Arguments

• x.var: The column of y (response variable) values plus detection limits
• cens.var: The column of indicators, where 1 (or TRUE) indicates a detection limit in the y.var column, and 0 (or FALSE) indicates a detected value in y.var.
• dist3: Name of the third distribution to be plotted, default is norm (normal distribution). Alternate third distribution is weibull(for Weibull distribution). Log-normal and gamma distributions are always used.
• Yname: Optional – input text in quotes to be used as the variable name. The default is the name of the y.var input variable.

Returns

prints a plot of the empirical CDFs with BIC value for each distribution.

Examples

data(Brumbaugh)
cenCompareCdfs(Brumbaugh$Hg,Brumbaugh$HgCen)

# With Weibull distribution
cenCompareCdfs(Brumbaugh$Hg,Brumbaugh$HgCen,dist3="weibull")

# Using an distribution not supported by this function (yet)
# you will get an error message
## Not run: cenCompareCdfs(Brumbaugh$Hg,Brumbaugh$HgCen,dist3="beta")
# With Yname specified
cenCompareCdfs(Brumbaugh$Hg,Brumbaugh$HgCen,Yname="TCE Conc (ug/L)\nLong Island, NY USA")

References

Helsel, D.R., 2011. Statistics for Censored Environmental Data using Minitab and R, 2nd ed. John Wiley & Sons, USA, N.J.

Delignette-Muller, M., Dutang, C., 2015. fitdistrplus : An R Package for Fitting Distributions. Journal of Statistical Software, 64, 1-34. http://www.jstatsoft.org/v64/i04/.