Percentile Settings
Percentile Settings
If you want to use percentile calculation you must enter your desired values here:
Please enter your values for Percent and your desired intervals.
The coverage limit should also be set to avoid that the calculation is incorrect in the case PRTG’s monitoring is stopped for a short time.
Continuous percentile interpolates between discrete values (this is the recommended setting), whereas discrete percentile chooses the next smaller discrete value.
Continuous percentile basically means that the measurements are treated as a statistical population and the value is determined by interpolating a value when it isn’t present. This means that values are interpolated between actual measurements that are varying around the „perfect” center of the measurements.
Discrete percentile means that the value must be a member of the data set. For this kind of calculation you require a discrete distribution. The median of a discrete distribution can not be defined, as such, meaning that the 50th discrete percentile may not necessarily be the median if the value does not belong to an odd number of measurements. Discrete percentiles, as such, should not be used for billing applications.
A good source for more information regarding these percentiles can be found on this page: http://www.servicelevel.net/rating_matters/newsletters/issue13.htm