n_audio = length(levels(tlx$audio)) par(mfrow = c(1,n_audio)) for (i in levels(tlx$audio)) { boxplot(tlx_overall~guidance, outline=FALSE, data=subset(tlx,audio==i), main = "All Data", xlab = i, ylab="TLX (Overall)", cex =1, cex.lab = 1, cex.main=1, cex.axis=1, pch = 23, col = 3, lwd=.5) } dev.copy2pdf(device = quartz, file = "tlx_per_audio_x_guidance.pdf") dev.off ();