Question

For each of the following say whether it is a random variable. If yes, write its probability mass function.

(a) the number of double sixes when rolling two fair dice 24 times.

(b) the number of correct questions in an exam with 8 true or false questions by a student who answers all questions at random.

(c) the number of orange marbles in a simple random sample of 5 marbles from an urn that contains 20 blue and 40 orange marbles.

(d) the number of orange marbles in 7 draws with replacement from an urn that contains 20 blue and 40 orange marbles.

(e) the number of red marbles in a simple random sample of 6 marbles from an urn that contains 20 red, 30 green, 40 yellow, 50 blue marbles.

(f) the number of red marbles in 8 draws with replacement from an urn that contains 20 red, 30 green, 40 yellow, 50 blue marbles.

Answer 1

First Understands,A random variable is a variable whose value is a numerical outcome of a random phenomenon.

Out of six statements all comes under random experiment as chances of occurring of events are same and random.