Running totals show what has piled up, while rates show how fast it changes....

https://storyquanta.com/s/eroIh5770ECD5iCO7W72u

Running totals show what has piled up, while rates show how fast it changes. Use parcels and rainfall to see why units and time windows matter: parcels by noon differs from parcels per hour, just as daily inches differs from inches per hour