90th/95th/99th Percentile?

[dredd]

Hi all,

I am new to Cognos Report Studio so i need some help from the gurus here. :)

I am trying to calculate the 90th/95th/99th percentile.
When i use the formula below..the result is 0.

Percentile([Base LAN/WAN Measurements].[Bandwidth Utilization In])=0.95

There is data in the component that i am trying to calculate as i have tried using Max, Min formula to confirm.

I would appreciate it very much if someone can help me out. :)

[Lynn]

The expression you wrote looks like a filter, not a query item calculation. It has "=0.95" at the end.

If you include the query item in your layout (without the =0.95) at the end, make sure you set the data format property in the layout. Perhaps you are seeing zero because the precision isn't shown?

You might also look at using the "for" option to set the scope for the calculation, such as

Code Select Expand


Percentile( [Base LAN/WAN Measurements].[Bandwidth Utilization In] for report)


or maybe

Code Select Expand


Percentile( [Base LAN/WAN Measurements].[Bandwidth Utilization In] for [SomeOtherQueryItemInYourReport])


[blom0344]

Percentile calculations and filters are a non-marriage.  The chance of having a 'real' dataset where you can isolate the 95th percentile is almost zero.
When lining up the data you can identify the row with the value just under 0.95 and the next one just over that value with larger sets of data. With a set of 20 rows with different values selecting the 95th by filter works

[dredd]

yes..i am trying to find the 95th percentile for a dynamic set of records..

if i use the

Percentile([Base LAN/WAN Measurements].[Bandwidth Utilization In] for report) formula..
it doesn;t show me what i want..

so how am i going to find the percentile for this particular data object? there are at least 1k samples (sometimes more...)

[dredd]

heres something to better illustrate what i am trying to achieve....

lets say i have 5 elements..over a period of 5 days..i want to find out what was the 95th percentile of each element...

[blom0344]

Got a feeling you need the following (based on Excel):

http://www.techonthenet.com/excel/formulas/percentile.php

where an array is used to compute the 95th percentile

[dredd]

how do i specify array in cognos?
Cos the number of records is dynamic