[R] cenboxplot(): Reporting Limit Twice Correct Concentration

[Nordlund, Dan (DSHS/RDA)]

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Rich Shepard
> Sent: Tuesday, September 04, 2012 4:15 PM
> To: r-help at r-project.org
> Subject: [R] cenboxplot(): Reporting Limit Twice Correct Concentration
> 
>    I've gone over the data and do not see my error; the dput() output
> of the
> data frame and the pdf output of cenboxplot() are attached.
> 
>    The command used:
> 
> cenboxplot(sb.t$quant, sb.t$ceneq1, range=1.5, main='Total Recoverable
> Antimony', xlab='Pre-Mining Era', ylab='Concentration (log mg/L)')
> 
> (on a single line in emacs).
> 
>    The RL on the plot is drawn at 0.01 rather than at 0.005 and I'd
> like to
> learn why.
> 
> Rich

Rich,

The line is drawn at the maximum censored value.  

>max(sb.t$quant[sb.t$ceneq1==TRUE])
[1] 0.01

The line is drawn at 0.01 because there is a censored record where quant=0.01, i.e.

>sb.t[which(sb.t$quant==0.01 & sb.t$ceneq1==TRUE),]
      site   sampdate        era param quant ceneq1 floor ceiling
34169 MW-5 1995-01-10 Pre-mining SbTot  0.01   TRUE     0    0.01



Hope this is helpful,

Dan

Daniel J. Nordlund
Washington State Department of Social and Health Services
Planning, Performance, and Accountability
Research and Data Analysis Division
Olympia, WA 98504-5204