The EC50 for the seedling growth was determined by expressing each treatment as a proportion of the control seedling growth by the Trimmed Spearman–Karber method (Hamilton et al., 1977). The computer program SPEARMAN (USEPA, 1999b), provided by US EPA's Center for Exposure Assessment Modeling (CEAM) was used to estimate EC50 values.
Trimmed Spearman-Karber Method. A simple nonparametric method to determine median effective doses (LD50, etc.) from dose-response curves. This package is based on the paper by Hamilton et al (1977, 1978).
To install, just type this in your R session: Marzocchi 888 rcv 2007 service manual.
The package contains one function,
?tsk in your R terminal for detailed help on the function. An example:
This code was written several years ago. It runs and produces valid results, but may not be written in a contemporary R idiom.
This package was formerly located at https://r-forge.r-project.org/projects/tskarber/ . The R-forge project is being kept around to direct any existing users here. Any future updates will happen on Github.
Hamilton, M. A.; Russo, R. C.; Thurston, R. V. Trimmed Spearman-Karber Method for Estimating Median Lethal Concentrations in Toxicity Bioassays. Enviro. Sci. Tech. 1977, 11 (7), 714-719. http://dx.doi.org/10.1021/es60130a004
Ibid, 1978, 12 (4), 417. http://dx.doi.org/10.1021/es60140a017