Meaning of OSCAR statistics terms
Greetings. I am trying to get better using and understanding OSCAR. I am unsure about the meaning of the statistics terms: minimum, the median, 95% and 99.5%.
Two seem fairly clear:
Minimum - the minimum value seen that night?
Median - the median value of all values seen that night?
The last two values I am very unclear on: 95% and 99.5%
Can you help me understand what these two values represent ? And what is the utility of designating them this way?
Thanks so much!
RE: Meaning of OSCAR statistics terms
The last two could be written 95 percentile and 99.5 percentile, but that would mess up the table formatting
A 95 percentile value means that 95% of all the values are at or below the given value.
Likewise, the 99.5 percentile value. It is, in effect, the maximum value excluding any distant outliers.
The median is the 50 percentile value, not the mean or average value.
Apnea Board Monitors are members who help oversee the smooth functioning of the Board. They are also members of the Advisory Committee which helps shape Apnea Board's rules & policies. Membership in the Advisory Members group does not imply medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
RE: Meaning of OSCAR statistics terms
Ahhh excellent explanation. Thank you.
That brings up the question as to why we care about 95% vs 99.5%
Seems odd to me.
RE: Meaning of OSCAR statistics terms
The 95th percentile is the more useful of the two. The reason there is a 99.5 percentile at all is because that is what ResMed machines report as maximum values. Other machines report an actual maximum value, and the column is labelled Max rather than 99.5% for those machines.
RE: Meaning of OSCAR statistics terms
Super, and why is the 95% value useful? Is it because it throws out wild transient values that are outliers? How does this 95% value change thinking when evaluating a set of CPAP Oscar numbers? How would one actually use that bit of info?
Thanks so much on adding to my understanding!
RE: Meaning of OSCAR statistics terms
It's just the "worst" 5% of leakage.
RE: Meaning of OSCAR statistics terms
For flow limits the 95% value is what we check as min and med are rarely anything but zero. 0.10 is what we arbitrarily use to determine if flow limits are being adequately treated.