standard deviation

[epithymia]

Hey,
having problems with a formula...
I am trying to do a standard deviation on a formula (in CR 8.5), and won't let me do it because it says "summary could not be created". I assume this is because it is trying to do the standard dev on a running summary already.
Won't let me do it! I can calculate standard dev on each record, but that doesn't give me the number I am looking for.
I guess??? I have to do it with a whileprintingrecords option, but not sure how.

Any ideas?

 

[dgillz]

How can you caluclulate a StdDev on each record when it takes at least 2 values for a StdDev?

Also if you are trying to StdDev() a formula field, please post ths formula.

Software Training and Support for Macola, Crystal Reports and Goldmine
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dgilsdorf@mchsi.com

 

[epithymia]

I am trying to do a standard deviation on a summary. this is what seems impossible.

 

[dgillz]

Are you trying to do a StdDev of a formula field? If so please post the formula.

If not, just right click the field, (the field in the details section, not the summary operation) select insert summary, make it a StdDev and you are done. Software Training and Support for Macola, Crystal Reports and Goldmine
251-621-8972
dgilsdorf@mchsi.com

 

[epithymia]

need to do a standard deviation of this formula:

Sum ({dApplicationStat.CallsAnsweredDelay}, {dApplicationStat.Timestamp}, "daily&quot/Sum ({dApplicationStat.CallsAnswered}, {dApplicationStat.Timestamp}, "daily&quot

So, really, a standard deviation of a sum. So the result would be a constant for each day of the month and I can create upper and lower control limits.

Thanks!

 

[dgillz]

If you don't use the summary operation in your StdDev formula, and instead just use the database fields you have listed above, what happens? Is it not returning the expected results? Have you tried this yet?

This is what I mean by doing a StdDev of the database field and not the summary.
Software Training and Support for Macola, Crystal Reports and Goldmine
251-621-8972
dgilsdorf@mchsi.com

 

[epithymia]

thanks for the help, but I don't think you get it. let me try again and be as explicit as possible.

Looking for an ASA which is: answer delay over calls answered.

There are 10 skill sets this is worked on.

So I can get the ASA per skill set per day, and ALSO GET THE ASA FOR ALL SKILLSETS TOGETHER PER DAY.

I have no problem getting and graphing a STDEV for all the ASA's per skillset per day. Easy. But once I try to get the STDEV for the general ASA for the day, it seems impossible. What I want to do, according to crystal, is sort of a SUM OF A SUM, in a way. And it won't let me. I think, the only answer has to do with whileprintingrecords, but I haven't quite figured that out...(can do a sum like that easy...but not a STDEV).

thanks again

 

[dgillz]

OK, now I am starting to see it.

You need to use whilePrintingRecords and assign each of the elements you want to do a StdDev on to a numbervar Array in the group footers.

Then later (report footer?) do a formula that takes the StdDev of the array. I have never done this but I am sure it will work.

Hopefully this gives you something to think about. I will play with this a bit myself alter on but I have to leave right now. Thanks for taking the time to fully explain the issue. A lot of people never do that.

Software Training and Support for Macola, Crystal Reports and Goldmine
251-621-8972
dgilsdorf@mchsi.com