The data frame
TIREWEAR contains measurements for the amount of tread loss in thousandths of an inch after 10,000 miles of driving.
A data frame with 16 observations on the following 3 variables:
wear (tread loss measured in thousandths of an inch)
treat (a factor with levels
block (a factor with levels
Ugarte, M. D., Militino, A. F., and Arnholt, A. T. 2015. Probability and Statistics with R, Second Edition. Chapman & Hall / CRC.
par(mfrow=c(1, 2), cex = 0.8) with(data = TIREWEAR, interaction.plot(treat, block, wear, type = "b", legend = FALSE)) with(data = TIREWEAR, interaction.plot(block, treat, wear, type = "b", legend = FALSE))par(mfrow=c(1, 1), cex = 1)