standard deviation wrong

Answered
Patrick LAMOTTE asked on November 20, 2018

Hi,
it seems that we have wrong results for standard deviation when there is one parameter or when there are n parameters with the same value. See attached file.
In the first (sd-one-value) we've got sometimes 0 (which is the right value) or the param's value.
In the second, sometimes 0, sometimes a very small value (I guess it is because there a small difference between average and param's value)
how ca we fix that ?
Thanks
Patrick

7 answers

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Dmytro Zvazhii Dmytro Zvazhii Flexmonster November 20, 2018

Hello Patrick,
Thank you for writing.
Could you please provide us with the example where the issue is reproducible?
That will definitely help us in our further investigation.
Waiting to hear from you.
Regards,
Dmytro

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Patrick LAMOTTE November 21, 2018

Hi Dmytro,
Attached is a video which will show an example of a mix of wrong and good SD.
unfortunatly, video file is not accepted, so I attached a screenshot, let me know if it is enough
Thanks
Patrick

Attachments:
wrong_and_good_sd.png

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Tanya Gryshko Tanya Gryshko Flexmonster November 21, 2018

Hello, Patrick,
Thank you for your fast response.
Here is a JSFiddle sample with a demo close to your screenshot: https://jsfiddle.net/flexmonster/5wLfjom7/. It seems to be working as expected. Could you please modify it so that the issue is visible there?
Waiting for your feedback.
Regards,
Tanya

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Patrick LAMOTTE November 22, 2018

Hi Tanya,
Thanks.
I tried to play with values but I can't reproduce the problem we've got in our web site but as you can see in the attached file we should not get sometimes 0 and sometimes the value in SD.
In your fiddle, SD is always equal to the value, is it normal behavior ? it should 0, shouldn't it ?
best
Patrick

Attachments:
sd-1-value.png

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Ian Sadovy Ian Sadovy Flexmonster November 22, 2018

Hello Patrick,
 
Thank you for the answer.
Actually, you are right. SD for single value should be 0 and there is a mistake.
It will be fixed in the next minor release (ETA Dec 03).
 
As for the very small values, we recommend applying a number format to round the values.
 
Hope it helps.
 
Regards,
Ian

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Dmytro Zvazhii Dmytro Zvazhii Flexmonster December 4, 2018

Hello Patrick,
We are glad to inform you that the version with the fix has already been released.
You are welcome to update the component.
Regards,
Dmytro

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Patrick LAMOTTE December 5, 2018

Great, thank you Dmytro and have a nice day

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