Statistic sensor. Get the correct mean value at the end of max_age

Configuration
1

Hi,
I have this sensor:

sensor:
  - platform: statistics
    name: "Potenza media 1 Piano"
    entity_id: sensor.sonoff_power
    state_characteristic: mean
    sampling_size: 5  
    max_age:
      minutes: 1

Every minute the statistic sensor will be reset (max_age) indipendently from sampling_size. I need to get the last sensor value before the reset, that correspond to the correct mean value in a minute. Is it possible? Without using automation or secondary sensor. Can help age_coverage_ratio or buffer_usage_ratio attributes?

Thanks

2

Hey,
the sensor does not reset every minute.
Every reading from your source sensor (sensor.sonoff_power) will be considered for exactly 60 seconds in the computation of your statistics. That means, if your sonoff device has a telemetry period of 15 seconds, the statistics will be computed from 4 sensor readings at any given time.

I need to get the last sensor value before the reset, that correspond to the correct mean value in a minute.

I did not understand your intent.