First, nobody asked you to spell check your work, but there is a certain level of grammar that one would expect to be innate and come easily to any semi-cogent human being. For example, knowledge of the word "about" which apparently escapes you.
I would argue that grammar serves as a decent indicator of intelligent (up to a point). You can't tell that someone is a genius from their writing style, but you can tell if they are a raving lunatic. I would expect nearly ALL mildly intelligent people to have nearly impeccable grammar because grammar skills are very easy to learn relative to what a person needs to learn to be considered "intelligent." Every intelligent person has to be exposed to writing (in their native language) in order to read textbooks and communicate...
However, the arbitrary skills on an IQ test, like selecting patterns out of symbols, have no direct relation to anything and doing well on them proves nothing (in my opinion).