3 Replies Latest reply on Jul 3, 2015 7:11 AM by tai.jin

# How to get the % of data that are 1*sigma (standard deviation) away from the average

I have a Table A with a time field and a "value" field, with a lot of records, and a Table B with 3 records, where I want to store the average of the table A values during last month (M-1), M-2 and M-3, as well as the standard deviation for each month, and the percentage of records that are 1*sigma away from the average for each month. I related Table A with Table B by the month number and I managed to get the standard deviation of Table A::value for each month by stdev function. But how can I calculate the % of records 1*sigma away from the average?

I tried to add a field of calculation in table A which is abs(Table A::value - Table B::average), but it doesn't get any result. Maybe because the Table B:average is already a calculation of Table A related to Table B, so it can't be used in Table A?

• ###### 1. Re: How to get the % of data that are 1*sigma (standard deviation) away from the average

This sounds more to me like something where you would do your calcs (Ave and StDev and 1*sigma off Ave) in Table A, then post the result in Table B.

• ###### 2. Re: How to get the % of data that are 1*sigma (standard deviation) away from the average

Shouldn't matter where the data for the calculation comes from.

Have a look into the attached file.

• ###### 3. Re: How to get the % of data that are 1*sigma (standard deviation) away from the average

I did pretty much the same thing as you did in your file, but it doesn't work...

So I started over and it works now!

It happens to me very often that a thing doesn't work in Filemaker, but works when I delete and redo it...

Thanks for your time any way