One of the events at the recent McKinley Middle School Carnival was a contest to see who could launch a water balloon the farthest using a giant slingshot. In the carnival's first 30 minutes, 12 students launched balloons. The median distance the balloons flew was 125 feet, and the interquartile range was 70 feet. None of the balloons flew more than 185 feet. Which is a measure of how much the distances flown by the balloons varied?