Nominal with quantitative variables

These comparisons are often examined using basic bar charts or, in the following example, using side-by-side box-plots. These boxplots give very clear comparisons.

The following code simulates two ad campaigns A, and B with two different outcomes:

set.seed(123)  
rows=100 
a <- data.frame(Sales=rnorm(rows,mean=75,sd=5), 
                Treatment=factor(c("Campaign A"))) 
b <- data.frame(Sales=rnorm(rows,mean=80,sd=5), 
                Treatment=factor(c("Campaign B"))) 
combined=rbind(a,b) 
#Boxplots which compare treatments  
boxplot(Sales~Treatment,data=combined, main="Comparing Treatments",  
          xlab="Treatment", ylab="Sales")