In my last post, I mentioned that I had taken a practice ACT writing section without reading the passages. I used certain rules for deciding which choice to answer that take advantage of the odds of particular types of answers being correct. If the question was testing punctuation, the rule was that I had to choose the answer with the least punctuation. I did this even in cases when the choice was obviously incorrect even within the answer choice. For example, if one of the choices was "the teachers classroom" I would have to choose it (no punctuation obviously being the least punctuation) even though the correct choice clearly needs an apostrophe. If two choices tied for least punctuation I had other methods (such as "odd man out") to break the tie.
Among the punctuation questions, my choice was correct about 40% of the time - far greater than one would expect from random guessing. When my choice was incorrect, the choice with the next least punctuation would have been right about 40% of the time. The choice with the most punctuation was almost never right.
Now, obviously, it is best to know your punctuation rules and to choose your answers based on which choice you know to be correct. However, if you must guess from among two or more choices, you should go with the odds and choose the one with the least punctuation, or, at the very least, eliminate the choice with the most punctuation.