calculating percentile 90%

[johangel]

I have a list with result and percentiles like:

value     percentile
2608      65%
1256      30%
.            .
.            .
In the report I have to do a calculation where I need to use the value where the percentile = 90%.
How can I calculate this?
thanx,
Johan

[jshanks]

Johan,

Can you add a calculation that evaluates your percentile column?  Something like what is listed below:

if ( [percentile] = .90 ) then ( [value calculation] ) else ( 0 )

[johangel]

jshanks, it works.
But I have now 10 zero's and 1 percentile90% in my list
How can I use the calculated percentile90% in other calculations?
for instance :when I want log(percentile90%) , cognos give of course an error: log(0 ) is impossible.
Next formula I need to use:
(log(percentile90%) - log(125))*(other calculated variable)
sincerely,
johan