The numbers 4, 5, 6, and 7 are on a spinner. You spin the spinner twice. Which calculation proves that landing on an even number for the first spin and the second spin are independent events?

We can determine this by looking at the odds of getting an even number on the second spin given an even first spin and an odd first spin. If you look at both situations, there is still a 50% chance of getting an even number on the second spin. Given this fact, we can tell that the first spin doesn't affect it and therefore they are independent events.