Assume that when adults with smartphones are randomly selected, 63% use them in meetings or classes. If 8 adult smartphone users are randomly selected, find the probability that exactly 3 of them use their smartphones in meetings or classes. The probability is (Round to four decimal places as needed.) Assume that when adults with smartphones are randomly selected, 62% use them in meetings or classes. If 20 adult smartphone users are randomly selected, find the probability that exactly 15 of them use their smartphones in meetings or classes. The probability is (Round to four decimal places as needed.) Assume that when adults with smartphones are randomly selected, 59% use them in meetings or classes. If 6 adult smartphone users are randomly selected, find the probability that at least 2 of them use their smartphones in meetings or classes. The probability is. (Round to four decimal places as needed.) Assume that when adults with smartphones are randomly selected, 59% use them in meetings or classes. If 6 adult smartphone users are randomly selected, find the probability that at least 2 of them use their smartphones in meetings or classes. The probability is. (Round to four decimal places as needed.) When studying radioactive material, a nuclear engineer found that over 365 days, 1,000,000 radioactive atoms decayed to 977,010 radioactive atoms, so 22,990 atoms decayed during 365 days. a. Find the mean number of radioactive atoms that decayed in a day. b. Find the probability that on a given day, 53 radioactive atoms decayed. a. The mean number of radioactive atoms that decay per day is (Round to three decimal places as needed.) b. The probability that on a given day, 53 radioactive atoms decayed, is (Round to six decimal places as needed.)