In this workout, we want to practice using data validation. At the moment, we've got a match function and that match function is matching the words best case to a potential list. At the moment, I can see that best case in blue which is my inputs, matches to the first in my list best case. Thus it returns a one. I've then got three functions working off of that choose, offset, and index, and they are taking the first of the sales growth, 10%. What we want to do is use data validation on that input best case. So I use my shortcut Alt + AVV and data validation pops up. It asks me first for the criteria. What do I want to allow? And I want to allow a list. Now my source for a list is going to be B8 to B10. I only want users to choose either best case, base case, or worst case.

Next up, users need an input message to help them navigate what I've designed. So I give that a title, Scenario Picker, and the input message says, choose your scenario from the list below.

Lastly, I need an error alert in case they do the wrong thing. I'm going to choose a warning. Again, I'll use the same title being Scenario Picker.

And then I need to tell them that they've done something wrong. So you must only choose valid scenarios from the list provided. So if I press OK, we now see that input message pop up. If I navigate away from that and then come back again, that input message comes up. Choose your scenario from the list below. As I hit the down arrow, I can now choose from those three, base case and worst case, and the functions change as I do that. If I were accidentally to type in this cell something that was not allowed, the error message pops up and I can then click Cancel.