Smartthings, DHT sensors and history

I am using a connected development board with 5 DHT sensor.s The board is connected through my connected cloud account to my Smartthings hub. So far everything works great to monitor temps in my home.

The smartthings device for each sensor provide a history button which provides a graph of the temps in the interval set in the connected app for each DHT. I also provides the min OR max temp if the day button is selected.

Does anyone know how it determines which temp to show for the hour and day? How does it determine max or min temp? It also shows what looks like an average line in the chart. How is that calculated?

Any info would be appreciated. Thanks in advance.