A package delivery company wants to satisfy customer expectations of on-time delivery. Therefore, an analyst wants to see whether the reliability of delivery vehicles, the number of deliveries per driver, and traffic have any statistically significant relationship with on-time delivery during the DMAIC Assessment phase. An important step in this effort is to define the variables. In this scenario: The only independent variable is traffic because it is outside the company's purview. The dependent variable is on-time delivery. The dependent variables are the reliability of delivery vehicles, the number of deliveries per driver, and traffic. The only dependent variable is vehicle reliability, as without vehicles you can't deliver