See how a running total differs from a rate of change using parcel deliveries...

https://gracesinsightfulinsight.publishlane.com/posts/why-is-an-average-rate-a-summary-and-not-the-full-story

See how a running total differs from a rate of change using parcel deliveries and rainfall. The article explains what each number counts, why units matter, and how choosing a time window—an hour, a day, or a week—changes what a chart can tell you.