Final answer:
Speeding is the most common traffic violation among teens, making up about 50% of all violations. The violation data can be analyzed statistically to determine the independence of speeding and cell phone use while driving.
Step-by-step explanation:
The most common violation that constitutes approximately 50% of all teen traffic violations is speeding. This information is supported by statistical data from traffic studies as it is a frequent cause for concern regarding teen driving safety. For instance, when studying the relationship between speeding violations and cell phone use while driving, it was observed that these events are independent. If we had a hypothetical study where 755 drivers were surveyed, and we knew how many had speeding violations and how many used cell phones while driving, we could calculate the expected number of drivers who did both to see if they are truly independent. Using the given data: 70 had a speeding violation, 685 did not; 305 used cell phones while driving, and 450 did not; we can calculate the probability of both events occurring (speeding and cell phone use) and compare it to the expected value if they were independent events.