00:01
In this question, we consider this scenario where there is a multiple -choice test that has six questions on it.
00:09
Each of the questions has four answer choices, and we are asked for the probability of answering at least one question correctly.
00:17
So let's define the random variable x as the number of questions guessed correctly or answered correctly.
00:25
An assumption i'm making here is that for each question, we are just randomly guessing at each question.
00:31
In that case, the probability of getting any individual question correct is one out of four.
00:38
And that's because there's four answer choices, one of which is correct.
00:42
So therefore, a random guess has a chance of one out of four of being correct.
00:47
So in this case, each of the six questions can be thought of as bernoulli trials, having two outcomes of interest, either guessed correctly or not.
00:56
And if we are randomly guessing, then their outcomes are independent...