I was wondering if there is a way to avoid using `t.test()` 3 times for comparing 3 variables `x1`, `x2`, and `x3` and instead using `t.test()` one time to take any two variables at a time inputted to it? 

For example, for: `x1 = rnorm(20) ; x2 = rnorm(20) ; x3 = rnorm(20)`, I'm now using: `t.test(x1, x2) ; t.test(x1, x3) ; t.test(x2, x3)` but could I just use `t.test()` one time?

**Here is what I tried with no success:**

```
t.test(cbind(x1, x2, x3))

```