If it's a 9:3:3:1, then it's typical Mendelian ratio... but here's the thing:
If you got something like 11: 9: 1:1 then you would see that the 1's would be the recombinants. Usually those mendelian ratios means that the two traits are inherited together, but that they aren't linked. So in other words..
Tall = T
Short = t
Yellow = Y
white = y
when you do the cross, you should get a 9:3:3:1, unless they are linked. If linked, you won't get this clean ratio.
Here's another way to think about it.
For a linked trait:
Draw out two vertical lines ---A------Y---- Parent 1 (AAYY)
---a------y---- Parent 2 (aayy)
if the kids end up with like:
------a----Y-----
or
-----A-----y-----
Then those are the recombinants because they don't like look either of the parental combinations.. so in other words.. if the progeny look like a parental cross, then probably not linked, but if they look like something else other than that, then the genes may be linked. If all else fails, just look for weird ass numbers.. that usually works.. sorry that was so confusing, kind of hard to draw on SDN