A one sample t-test enables us to test whether two means are significantly different; a two sample t-test allows us to test whether the means of two independent groups are different. In this recipe, we will discuss how to conduct one sample t-test and two sample t-tests using R.
mtcars has already been loaded into a data frame within an R session. As the
t.test function originates from the
stats package, make sure the library,
stats, is loaded.
Perform the following steps:
amusing a boxplot:
> boxplot(mtcars$mpg, mtcars$mpg[mtcars$am==0], ylab = "mpg", names=c("overall","automobile")) > abline(h=mean(mtcars$mpg),lwd=2, col="red")