There's a tracker item you can vote for to draw a little more attention to this issue:
https://tracker.moodle.org/browse/MDL-51930
..and while you're at it, you can also vote for this one to get the equally missing option for dependency ranges or multiple values. As in:
Q: Do you like cheese on a scale from 1(no) to 6(yes)? A: 6,5 --> Q: Looks like you love cheese, which kind of cheese is your favorite?
Q: Do you like cheese on a scale from 1(no) to 10(yes? A: 4,3,2,1 --> Q: You're not a big cheese fan, let's talk about brownies.