Random numbers can be really useful for generating test data, among other things, so here's how to generate all the numbers you want in Excel:
Rand is a great function and will generate a ranom integer
This will generate a random integer between 5 and 20.
This will generate a random double between 5 and 5+15 (20) and I'm not sure right now why this works! but it does.
remember that any random numbers that you generate will change when the worksheet that you're on recaulculates unless you paste their values out, which is something that I find frequently necesarry. Happy camping.