Results of the randomization study, demonstrating the relationship between the log area under the curve (AUC) and the pVAX:Luc DNA concentration, needle depth, and tattoo duration for the Aella tattoo machine. Log AUC is visualized as a box plot (showing the lowest observation, the lowest 25% of data, the median, the highest 25% of data, and highest observation). Lines visualize the predicted AUCs obtained from the model equation.