Statistical analysis applied to percutaneous absorption and cutaneous disposition of different types of jet fuels is presented. A slightly different question is addressed with methyl salicylate absorption, namely when one compound can be used as a simulant for another compound. A new graphical statistics method, called "Compass Plot", is introduced for displaying the results in the design of experiments, especially for balanced factorial experiments. An example of compass plots for visualizing significant interactions in complex toxicology studies is provided. It is followed by a simulation study on an approximated F-test to determine whether a random effects model is needed for the exponential difference model. A new multivariate coefficient of variation, used as an index to determine which effects have a random component, is also introduced and investigated by simulations and two real datasets.