Good Rhythm and Intelligence

Earlier this week, I found an article relating high scores on intelligence tests with the ability to keep good time. It is an interesting article, but it drew many questions from me.
1.) Do all intelligent people keep good time?
2.) Are all the people that can keep good time intelligent?
3.) Since it has been proven that music helps the brain, especially in the areas of critical thinking, was it the rhythmic accuracy that made the person intelligent or the intelligence that made the rhythmic accuracy? (which came first, the chicken or the egg?)
Okay, here's where I become the devil's advocate... (P.S. I'm a percussionist...it's our job to keep good time)
So.... what about all of the vocalists or other instrumentalists that always say, "Well, I'm just not good a rhythms" or are horrible at keeping time? (just a note: I hear that quote quite a bit and wonder how a person could consider themselves a musician without mastering not only pitch accuracy/intonation but rhythms as well). Does this mean they lack intelligence? I don't think so. While I do see where the researchers were going with their report, I think that looking at the basic principle that involvement in music generally helps the brain make connections and helps with critical thinking skills, thus resulting in higher scores on intelligence tests.