in a test for esp a subject is told that cards the experimenter can see but he cannot contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability .25 of guessing correctly on each card.

Question

in a test for esp a subject is told that cards the experimenter can see but he cannot contain  either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability .25 of guessing correctly on each card.

a)what is the mean number of correct guesses in many repititions of the experiment?

b)what is the probability of exactly 5 correct guesses?

bobpursley · Answer

mean: .25*20 exactly five in a row: (.25)^5