I have done loads of tests where I have guessed %26amp; to my surprise
got nearly all right.There are 10 questions on a true or false test. A student feels unprepared for this test and randomly guesses?
While the official probability is 50% to get 5 correct, it's tricker. Several questions in q sequence may have same answer. So you get more wrong or more correct unexpectedly by doing random choice.
However I would stick with normal probability and say you will get 30% chance to get 7 out of 10 correct for the kind of true/false test.
Probability of getting 7 correct (I presume you mean exactly 7, not 7 or more):
He has to get 7 questions right. The chance he'll get the first one right is 0.5. The chance he'll also get the second one right is 0.5*0.5 and so on - so 0.5 ^7
Then he has to get 3 wrong - 0.5 ^3
So the chance of getting 7 particular questions right and the other 3 wrong is 0.5 ^10 (This is a bit of an odd question because the chances of right and wrong are identical.)
And then you need to know how many different ways there are of selecting 7 questions out of 10 (because it doesn't matter which ones he gets right as long as it's 7 of them). I'm not going to do this for you, because it's basic - if you don't get it you really need to go back to your teacher and tell him you don't understand probability. I'm afraid that the other answers you have been given are from people who do not understand probability.
no clue, but i think i need that too cuz i just had i test today!!! haha
possibility is 70%.
If there is negative marking for wrong answer- don't do this %26amp; if not- check your luck
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