This article explains how a running total differs from a rate of change, using...

https://harperscooldigest.urbanvellum.com/posts/why-do-i-get-parcels-per-hour-instead-of-just-parcels

This article explains how a running total differs from a rate of change, using parcels delivered as an example. See why 120 parcels by noon is not the same as 30 parcels per hour, and how choosing the right time window makes a chart easier to read.