Emek and Luna were preparing to travel from their research station to a distant planet. Their computer stored travel times from six earlier missions on two possible routes. Route A had taken 31, 38, 39, 40, 41, and 47 hours. Route B had taken 36, 37, 38, 38, 39, and 40 hours. Emek and Luna organized the data on line plots. At first, Route A seemed tempting because its fastest trip took only 31 hours. But its times were spread from 31 to 47 hours, while Route B's times stayed between 36 and 40 hours. They also noticed that Route B's times clustered around 38 hours. Since they needed a dependable arrival time, they chose Route B instead of judging by the fastest trip alone. Their careful comparison paid off, and they reached the planet safely and on schedule.