1.) An urn contains 13 white balls and 14 red balls. A sample of four balls is selected at random from the urn. What is the probability that the sample contains two white balls and two red ones?
2.) An urn contains 14 red marbles and 13 blue marbles. 12 marbles are chosen at random. What is the probability that 6 red marbles are chosen?
3.) An urn contains 12 white balls and 5 green balls. A sample of seven is selected at random. What is the probability that the sample contains at least one green ball?
4.) A fair coin is tossed 9 times. What is the probability that the coin lands head at least 7 times?
5.) A fair coin is tossed 28 times. What is the probability that at most 26 tails occur?