ResMed S8 Elite Manual Clínico página 39

338210r3 Eng.book Page 33 Monday, July 11, 2005 1:28 PM
Statistics are provided for five time intervals (last day, last week, last month, last six
months, last year) so you can assess the significance of recent events.
All statistics calculated for a range of dates are median values. The median is the middle
value after the data have been sorted in order (50% of the values are smaller and 50%
are larger). For example, Table 6 presents one week of 95th centile leak data (values
in L/s). On day 7, the value 0.30 L/s would be displayed as the most recent day's leak
value. In column 3 of the table, the seven leak values have been sorted in increasing
order to calculate the median value.
Table 6: Sample calculation of median leak value
95th centile leak
Day
(L/s)
7
6
5
4
3
2
1
The median corresponds to the fourth value (0.30 L/s) in the ordered data set. The
value 0.30 L/s would be displayed as the most recent week's leak value.
If the data set had included an even number of days (eg a 30-day month), the median
would be the average of the middle two values in the ordered data set.
Notes:
a. The median is a more robust measure than an average (or arithmetic mean) for a data
set that has some extreme values. The average of the data in the above table is
0.39 L/s, reflecting the single session that had unusually high leak (1.00 L/s).
b. You may make the Efficacy and Usage Data screens available to your patient by
instructing them to press the Left and Right keys simultaneously. This does not give
access to the other parts of the clinical menu.
The Erase Data feature in Clinical Menu, Options enables you to remove all efficacy
and usage data stored in the device (except Run Hours). Machine settings are not
affected.
Ordered data set
(L/s)
0.30 0.20
0.20 0.20
1.00 0.30
0.20 0.30
0.30 0.30
0.40 0.40
0.30 1.00
D
ATA
Median value
(L/s)
0.30
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