Why would you want to guess in this type of test? This is not a test to to get a 100 and pass. This is a test to to find out how bad your hearing is to set your hearing aids to help you hear better. If you happen to have a good day and guess correctly in 50% of the words, wouldn’t that give an improper result for them to base the correction on the aids?
I think I would rather not guess, so that they can set the aids more correctly, so that I can, hopefully, hear and understand better.