# IQR (Interquartile Range) and Geometric Limits

I am having some trouble with the Geometric Limits.

I understand how IQR is calculated, but the report I am using applies Geometric Limits to the values before utilizing the IQR.

This is how they are describing Geometric Limits:
Geometric Limits
Nearly all the measures in ActionOI can have only positive values and have very long-tailed
distributions (Revenues, Costs, Discharges, Patient Days, Hours Worked, Hours Paid, Procedures
Performed, and other workload measures). Also, since Case-Mix Index and Area Wage Index (AWI)
can only have positive values, CMI-weighted and AWI-adjusted measures will be positive as well.
With measures of this nature, one can obtain better confidence limits by creating limits using a
lognormal distribution of these values (geometric limits), and then re-applying the exponential
function to return the values to the original scale for reporting. Geometric limits however cannot be
applied to measures however that have legitimate negative values, so combining geometric limits
calculations with the IQR method is far superior to using either alone.

So if these are my values:

239
6,852.00
9,383.00
10,411.00
11,874.00
13,190.00
16,705.00
16,831.00
18,902.00
19,947.00

How do you calculate the Geometric Limit?