fMonth <- factor(airquality$Month) # Convertit la variable "Month" en facteur. ozone.box <- ggplot(airquality, aes(x = fMonth, y = Ozone)) + geom_boxplot() solar.box <- ggplot(airquality, aes(x = fMonth, y = Solar.R)) + geom_boxplot() temp.box <- ggplot(airquality, aes(x = fMonth, y = Temp)) + geom_boxplot() wind.box <- ggplot(airquality, aes(x = fMonth, y = Wind)) + geom_boxplot()