If students can eliminate one or two answers, and are hesitating about the remaining two answers, it would be better to make an educated guess. If they have really no idea which of the four answers is correct, then it’s better not to answer at all. If students apply this method, it will give them an advantage in the end.
Students who answer randomly will have a final score close to zero. With one chance out of four of choosing the correct answer (and thus earning 5 points) and the risk of losing a quarter of the question’s value (1.25 points) with an incorrect answer, statistically they will end up with zero. On the contrary, a student who isn’t sure of the correct answer, but thinks carefully and is able to eliminate two answers out of the four, will have a distinct advantage.
Taking the time to think carefully before making a choice is clearly the best way to succeed. Of course, that is what we hope to teach our students in general: to think carefully before giving an answer!
You can find all the information about the grading process in our contest rules 'The Day of the contest' > 'Scores'.