Using summary function with nested groups

[hwwolfman]

I have a report developed with Crystal Reports 8.5 that shows histograms for various machine attributes. The data is grouped below the charts by values and machine names in that order.

I am trying to use the PthPercentile function as a selection criteria to knock out the top and bottom 5% as an error margin for the histogram. In the selection formula I am using this format:
{Machine.Cost} > PthPercentile(5,{Machine.Cost})

I am getting the error "The summary / running total field could not be created". I have tried using both group fields separately in the equation with no luck. Any thoughts?

 

[lbass]

You need to use this function in the group select, not the record select. Also, is it your intent to "knock out" the top and bottom 5% of all records? Or of records within groups? Your current formula (which I think you only displayed in part) would limit record selection to those greater than the bottom 5% of all records, if you used it in the group select statement. For a group select that creates a range within a group, do something like this:

Let's say you have a group on a field {Machine.Name}. Then

{Machine.Cost} > PthPercentile(5,{Machine.Cost},{Machine.Name}) or {Machine.Cost} < PthPercentile (95,{Machine.Cost},{Machine.Name})

should give you the middle 90% range of machine cost by machine name.

-LB