Help creating a basic function

Hi. First thing first, this appears to be a homework question, so please be aware of our homework policy. FAQ: Homework Policy. Please don't post homework questions verbatim like this.

A good place to get comfortable with R is the book, R4DS. It's free online at

It has a nice chapter on understanding and creating functions,

I'd work through this chapter and the examples provided, and see if you're able to create your function.

If you have specific questions, bring them back here. (Ideally with a reprex)