Need help writing validation script to make a dependent drop down

[bree40076589]

This is an example of what I need:

If Box A is filled in with "x", then Box B will display results "1,2,3,4,5".

If Box A is filled in with "y", then Box B will display results "6,7,8,9,10".

If Box A is filled in with "z", then Box B will display results "11,12,13,14,15"

And so forth.

Thanks for your help!