4. [-/4.54 Points] DETAILS ASWSBE14 5.E.016. The following table provides a probability distribution for the random variable y. y f(y) 2 0.20 4 0.30 7 0.40 8 0.10 (a) Compute E(y). E(y) = (b) Compute Var(y) and o. (Round your answer for o to two decimal places.) Var(y) = O = Need Help? Read It6. [224/454 Points] PREVIOUS ANSWERS ASWSBE14 5.E.037. You may need to use the appropriate appendix table or technology to answer this question. l According to a 2018 survey by Bankrate.com, 20% of adults in the United States save nothing for retirement (CNBC website). Suppose that 15 adults in the United States are selected randomly. (a) 15 the selection of the 15 adults a binomial experiment? Explain. The selection V a binomial experiment because the adults are selected V , p does nol change v V from trial to trial, the trials are independenl v V , and there are E outcomes possible. (b) What is the probability that all of the selected adults save nothing for retirement? (Round your answer to four decimal places.) E (c) What is the probability that exactly Four of the selected adults save nothing for retirement? (Round your answer to four decimal places.) E (d) What is the probability that at least one of the selected adults saves nothing for retirement? (Round your answer to four decimal places.)