How is 90th Percentile Calculated?

AIQ will exclude the last 10%, so it gives a value where 90% of values are less than or equal than the value.

AIQ stores the values of measurements, sorts them and then chooses the values which are closer to the desired percentile.

Very fast, but memory consuming

For example:

• If you have values 1, 2, 3, all the way to 1000, the 95th percentile will be 950.

• If you have values 2, 4, 6, all the way to 200, the 90th percentile will be 180.

That is the standard percentile calculation. The calculation is very fast, but it consumes a lot of memory.

AIQ performs some storing optimization for large amounts of measurements for bigger datasets to avoid having all of the measurements in memory. For a small dataset (less than 10 000) the data is identical.

For bigger sets of results (with the memory optimization used), the expected difference using our algorithm and the expected value is 0.099%. However, for smaller datasets was below that threshold.