The data frame `TIREWEAR`

contains measurements for the amount of tread loss in thousandths of an inch after 10,000 miles of driving.

`TIREWEAR`

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`A`

,`B`

,`C`

, and`D`

)`block`

(a factor with levels`Car1`

,`Car2`

,`Car3`

, and`Car4`

)

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)