A graph with statistical data is displayed at the top of the "Statistics" screen
Touch the curve with one finger, and without lifting your finger from the screen, slide it to the right or left to move between dates.
Tap once on the point of the graph to view the statistical data for a specific date. The transcript will be provided below the graph.
Touch the graph with two fingers and, without lifting your fingers from the screen, spread them apart ("stretch" the graph) to zoom in the graph. Similarly touch the graph with two fingers at once and bring them closer ("collect" the graph) to zoom out.
If you want to add data on another parameter of the device or data from other devices to the graph, tap on "Add another device" button and select the device from the list again.