Final answer:
The dependent variable is the time to finish the race, while the independent variable is the number of training miles.
Step-by-step explanation:
The dependent variable in this situation is the Time to finish the race. The dependent variable is the variable that is being measured or observed and is affected by the independent variable. In this case, the time to finish the race varies based on the number of training miles Diane runs. The number of training miles would be considered the independent variable.