00:01
For this problem, we are told that in a simple experiment designed to test esp, four cards, a jack, a queen, a king, and an ace are shuffled and then placed face -down table.
00:12
The subject then attempts to identify each of the four cards, giving a different name to each of the cards.
00:17
If the individual is guessing, we are asked to find the probability of correctly identifying for part a all four cards.
00:23
So for part a, our probability of, i'll write 4c for 4 correct, is going to be, well, first of all, we'd have the probability of choosing the correct card out of 4.
00:38
So i'll write that as, well, you'd have a 1 in 4 chance for the first guess.
00:43
And then if you've gotten that first guess correct, on the second guess, you're not picking between 4 cards, you're picking between 3.
00:54
So second guess is one in three.
00:57
And then the third guess, the third guess is going to be one in two.
01:03
And then for the last guess, if you've gotten all of the others correct, then process of elimination, you have to get the last guess correct.
01:14
So we'll have one over four times three times two, or one over four times six, so the probability is going to be one in 24...