Cut/Paste from the F1-help file:
fractile ( [ total [<fld {,fld}>] ] expression, fractile )
returns the aggregated fractile of expression iterated over the chart dimension(s).
The function argument expressions must not contain aggregation functions, unless these inner aggregations contain the total qualifier. For more advanced nested aggregations, please use the aggr function in combination with calculated dimensions.
If the word total occurs before the function arguments the calculation will be made over all possible values given the current selections but disregarding the chart dimension variables.
The total qualifier may be followed by a list of one or more field names within angle brackets. These field names should be a subset of the chart dimension variables. In this case the calculation will be made disregarding all chart dimension variables except those listed, i.e. one value will be returned for each combination of field values in the listed dimension fields. Also fields which are not currently a dimension in a chart may be included in the list. This may be useful in the case of group dimensions, where the dimension fields are not fixed. Listing all of the variables in the group causes the function to work when the cycle or drill-down level changes.
Examples:
fractile( Sales, 0.75 )
fractile( X*Y/3, 0.9 )
fractile( total Price, 0.25 )
fractile( total <Group> Price )
