A way to see if two things change together. If they change the same way, the covariance is positive. If they change opposite ways, it's negative. If they don't change together, it's zero.
We noticed a positive covariance between the number of hours studied and test scores.
It's like seeing how two things move together. If they move the same way, it's similar. This can help us understand how things are connected.
The covariance of two stocks can show if they tend to go up or down together.