
1. Re: Standard Deviation Over time
Tushar More Apr 13, 2018 12:47 AM (in response to ken school)1 of 1 people found this helpful 
2. Re: Standard Deviation Over time
ken school Apr 15, 2018 8:59 PM (in response to Tushar More)Hi Tushar,
noted and thanks for the update! Yes it showing a moving deviation now:
For my learning purposes, can i confirm that start: FIRST(), refers to first row, how about 0?
Also, the computed SD is different from using Tableau's distribution band. Please see below:
The SD shown is 1,283.137 using the distribution band. As such, how can I correctly perceived data in table form to identify deviation exceeding the upper threshold?
thanks!
Ken

3. Re: Standard Deviation Over time
Tushar More Apr 16, 2018 2:12 AM (in response to ken school)Ken,
Please mock up some data and share.
~Tushar


5. Re: Standard Deviation Over time
ken school Apr 16, 2018 9:20 PM (in response to Tushar More)Hi Tushar,
thanks so much again! it works! appreciate your help!
please see sample package workbook as attached. So essentially, the upper bound when using the tableau Standard Distribution band is computed as follows?:
WINDOW_AVG(SUM(COUNT)) + WINDOW_STDDEVP(SUM(COUNT))
thank you Tushar for your help so far!
Regards,
Ken

sample.twbx 34.9 KB


6. Re: Standard Deviation Over time
Tushar More Apr 16, 2018 10:18 PM (in response to ken school)Hi Ken,
The formula is used to find upper and lower bounds. As you can see it is correctly highlighting the values.
For my learning purposes, can i confirm that start: FIRST(), refers to first row, how about 0?
0 refers to current row. It is equivalent to running sum. So basically it adds values from first to current row in the partition.
~Tushar
If that helps, please mark the answer as helpful and correct.

7. Re: Standard Deviation Over time
ken school Apr 16, 2018 11:13 PM (in response to Tushar More)Hi Tushar, thank you so much!

8. Re: Standard Deviation Over time
Tushar More Apr 16, 2018 11:25 PM (in response to ken school)You are welcome Ken!