Probability Exam 2023 16. Determine the probability distribution's missing value. The probability that a tutor sees 0, 1, 2, 3, or 4 students on a given day. X 0 P(x) ? 1 0.15 2 3 4 0.20 0.20 0.25 A. 0.50 B. 0.80 C. 0.20 D. 1.0 17. The random variable x represents the number of credit cards that adults have along with the corresponding probabilities. Find the mean and the standard deviation. X P(x) 0 0.07 1 0.68 2 0.21 3 0.03 4 0.01 A. =1.23; =0.44 B. =1.23; = 0.66 C. =1.30;=0.44 D. =1.30;=0.32 18.One thousand tickets are sold at $1 each. One ticket will be randomly selected and the winner will receive a color television valued at $398. What is the expected value for a person that buys one ticket? A. -$0.60 B. $0.60 C. $1.00 D. -$1.00 19. A recent survey found that 60% of all adults over 50 wear glasses for driving. In a random sample of 90 adults over 50, what is the mean and standard deviation of those that wear glasses? A. =54;=7.35 B. =54;=4.65 C. =36;=7.35 D. =36;0=4.65 20. A recent survey found that 70% of all adults over 50 wear glasses for driving. In a random sample of 10 adults over 50, what is the probability that at least 6 wear glasses? A. 0.006 B. 0.200 C. 0.700 D. 0.850