W) {(8, 9), (2, 3), (0, -2), (10, -9)}
x) {(0, 0), (5, 10), (-3, 3)}
y) {(1, 1), (2, 2), (3, 3), (4, 4)}
z) {(-10, 1), (-9, 3), (-4, 5)}
which of the sets represent functions?

a. w, x
b. x, y,z
c. w, z
d. w, x,y, z

In a test for esp (extrasensory perception), a subject is told that cards only the experimenter can see 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 0.25 of guessing correctly on each card. a. the count of correct guesses in 20 cards has a binomial distribution. what are n and p? b. what is the mean number of correct guesses in 20 cards for subjects who are just guessing? c. what is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?