Running totals show what has piled up. Rates of change show how fast it adds...

https://www.lima-bookmarkings.win/learn-to-tell-a-running-total-from-a-rate-of-change-with-parcel-deliveries-120

Running totals show what has piled up. Rates of change show how fast it adds up. With parcels, 120 in a day is not the same as 10 per hour. This article explains how units and time windows shape what a chart tells you, in plain terms.