Restriktor is a free, open source R package for linear equality and inequality constrained statistical estimation, inference and evaluation for linear models.
Restriktor is implemented as an R package. This means that before installing restriktor, you should have installed a recent version (>= 4.0.0) of R. You can download the latest version of R from the R-project website.
Install Graphical User Interface (GUI)
R is a command line driven program. This means that it does not have a graphical user interface (GUI). Luckily, there are many good GUI's to make life easier, for example Rstudio, R Commander and RKWard.
Once you have installed R, the next step is to install restriktor. This can be done by typing in R:
install.packages("restriktor", dependencies = TRUE)
To check if the installation was successful, you can load the restriktor package and try for example:
library(restriktor) # construct constraint syntax based on the factor level names constraints <- 'GroupActive < GroupPassive GroupPassive < GroupControl GroupControl < GroupNo'
Fit the unrestricted linear model, where "Age" is the response
"Group" a factor with four treatment groups.
fit.ANOVA <- lm(Age ~ -1 + Group, data = ZelazoKolb1972)
# fit the restricted model restr.ANOVA <- restriktor(fit.ANOVA, constraints = constraints) # summary of the restricted parameter estimates summary(restr.ANOVA)
If you can see the output, everything is set up and ready.
For more information see the restriktor website.