Adding Measures of Central Tendency to Histograms in R

histdens2.R

png("beaverhistextra.png")
layout(matrix(c(1:2), 2, 1, 
	byrow = TRUE))
hist(beaver1$temp, # histogram
	col = "peachpuff", # column color
	border = "black", 
	prob = TRUE, # show densities instead of frequencies
	xlim = c(36,38.5),
	ylim = c(0,3),
	xlab = "Temperature",
	main = "Beaver #1")
lines(density(beaver1$temp), # density plot
	lwd = 2, # thickness of line
	col = "chocolate3")
abline(v = mean(beaver1$temp),
	col = "royalblue",
	lwd = 2)
abline(v = median(beaver1$temp),
	col = "red",
	lwd = 2)
legend(x = "topright", # location of legend within plot area
	c("Density plot", "Mean", "Median"),
	col = c("chocolate3", "royalblue", "red"),
	lwd = c(2, 2, 2))
hist(beaver2$temp, # histogram
	col = "peachpuff", # column color
	border = "black", 
	prob = TRUE, # show densities instead of frequencies
	xlim = c(36,38.5),
	ylim = c(0,3),
	xlab = "Temperature",
	main = "Beaver #2")
lines(density(beaver2$temp), # density plot
	lwd = 2, # thickness of line
	col = "chocolate3")
abline(v = mean(beaver2$temp),
	col = "royalblue",
	lwd = 2)
abline(v = median(beaver2$temp),
	col = "red",
	lwd = 2)
legend(x = "topright",
	c("Density plot", "Mean", "Median"),
	col = c("chocolate3", "royalblue", "red"),
	lwd = c(2, 2, 2))
dev.off()