Help with definition of Median Pressure Oscar

[bobm278]

My daily statistics on my Resmed S-10 include 95%, 99.5% and Med pressures. I cannot figure out how OSCAR calcluates the median. It is not simply the median of Min/95% or any other two values I can think of.

For example:
Min 95% 99.50% Med% Max% "Avg% From Statistics)"
15 16.18 16.76 15.20 16.86 15.33
Median Min/95% 15.59
Median Min/99.5% 15.88
Median Min/Max% 15.93
Median Min/Avg% 15.17

None of the calculations match the OSCAR Med. Statistics average comes close, but I don't want to have to check every day Right now, I check weekly but the only day that has the average is the current date.

[ChicagoGranny]

Of what value is checking the median pressure?

[ChicagoGranny]

BTW, OSCAR is continuously measuring the pressure. You don't have enough data to calculate the median of a continuous series.

[ozij]

The number reported by ResMed (Oscar) as the median pressure is simply the pressure at or below which you spent half the time.

A median is not an average.

[bobm278]

I built a historical data spreadsheet to track my data. Of all the pressure measurements available, the one I think is the best indicator of the night's performance is Average pressure. That value is available only on the morning after the night's sleep. I look at the data weekly. I would like to calculate the average pressure for each day without having to pull the SD card, open OSCAR and enter the data every day. The median seems to be the best starting point, but I was curious as to what two values it is using. I know the difference between median and average.

At the moment, I am calculating the virtual average as a percentage of median pressure. I took a 30-day sample of Average/Median and captured the average ratio. Using that ratio time median gives me a virtual average that is within 0.1 cmH2O which is pretty good. But in my career I have been an engineer and a business analyst and I am looking for more accuracy (my wife says I have kept half my career and am now simply anal).

[ChicagoGranny]

The median seems to be the best starting point

The best starting point for what?

[ozij]

The median seems to be the best starting point, but I was curious as to what two values it is using. I

A median using 2 values?
A median describe sa distribution.

The percentiles reported by ResMed (and thus OSCAR) indicate the percentage of time you spent below or at that pressure.
When you see a median pressure, it means you spent 50% of the time at or below that pressure.
The 90th percentile means you spent 90% of the time at or below that pressure.

ResMed records pressure and length of time at that pressure, and calculates the percentiles of time at pressure from the total time the machine was running.