What do the data of maximum altitude, average altitude, cumulative ascent and descent on the Redmi Watch 4 mean respectively?

For your reference, here are some details:
1. Maximum altitude is the maximum value taken from each unit time altitude value during your movement;
2. Average altitude is the average value taken by adding and dividing each unit time altitude value during your movement;
3. Cumulative ascent and descent is the accumulation of cumulative upward and downward data during your movement. Take cumulative ascent as an example, riding, there are 5 uphill slopes on flat ground, and the elevation of each slope rises by 8 meters, then the cumulative ascent of these 5 slopes is 5x8=40m (cumulative descent is the same as the cumulative summation of the difference in altitude of the descending slopes).