## Elementary Statistics: A Step-by-Step Approach with Formula Card 9th Edition

a. $0.324$ b. $0.676$ c. $0.999$ d. Events in (a) and (b) are complementary.
a. What is the probability that all 4 flights are on time? $p=0.9\times0.8\times0.5\times0.9=0.324$ b. What is the probability that at least 1 flight is not on time? $p=1-0.324=0.676$ c. What is the probability that at least 1 flight is on time? First find all are not on time: $p=0.1\times0.2\times0.5\times0.1=0.001$ so the probability that at least 1 flight is on time is $p=1-0.001=0.999$ d. Which events are complementary? Events in (a) and (b) are complementary.