Question on Statistics bar

[yankees123]

When you put your mouse pointer over on the left side where it says statistics,and you put it for example over leaks it says:
Rate of detected mask leakage(l/min)W-Avg:1.25  What exactly does this mean?  What is "W".  Does this mean the "normal expected leak" "rate?  It specifies a number like this with each individual statistic data.

Thanks.

[Walla Walla]

Got me. I'll take a shot though and say it's the waveform average.

[pholynyk]

It's Weighted Average. In Preferences, on the CPAP tab, you will find in the lower right corner a selector labelled 'Middle Calculation', with choices 'Median', 'Weighted Average', and 'Normal Average'.
On the Daily Page, in the statistics section, the labels are Min, Med, 90%, and Max. (The 90% label is actually whatever percentage you chose for Upper Percentile back in the CPAP Preferences; that's a display bug.) So Median is always displayed, whatever your choice for Middle Calculation, and Weighted Average is displayed in the Tool Tip, if you're interested.

[Walla Walla]

Yep. Not Waveform. What a stupid guess.

[yankees123]

Sorry for the dumb question, but what exactly does it mean by weighted average?
Still not sure what the number represents.  Thanks for your patience.
It seems like on the statistics,when you highlight a particular item it has a weighted number?

[pholynyk]

I knew somebody was going to ask that! It's not a dumb question.

As far as I can tell, It is a time-weighted average of the values for the session/night. For the items that are measured continuously - that is, graphed rather than flagged - it is the regular average over the time period. The median is the value that has half the measurements below, and half above. You can see that they are very often different; for ResMed machines, the Flow Limitation graph is a good example: On a good night, there will most often be a value of zero, with occasional values above zero. The median will most likely be zero, but the average will be above zero - the sum  of all the non-zero values divided by the number of all measurements.

I am not exactly sure because I don't yet understand exactly how the session data is kept internally.

[yankees123]

Thanks for the explanation.  I believe I have an understanding.  Great forum!!!