And then you use your random number generator to keep generating numbers from one to 80. And as long as you don't get repeats, you pick the first 30 to be your actual random sample. Another related technique, which is a little bit more old school, but is definitely the way that it has been done in the past and even done now sometimes, is to use a random digit table. You still start with these number associations with each student in the class, and then you use a randomly generated list of numbers. And so let's say that's our randomly generated list of numbers, and it keeps going well beyond this. And you start at the beginning. And you say, okay, we're interested in getting 30 two-digit numbers from one to 80, including one in 80.