stddev_pop producing incorrect results?

[nowjade]

Hi,

I’m trying to return  the standard deviation of a dimensionalized measure in an NDT but am getting incorrect results.

Data is as follows:

1. ID
2. Total Usage
3. Total Days
4. Avg Daily Usage
5. Std Dev. (of Avg Daily Usage)

Screenshot 1: Data

Columns 1-4 are dimensionalized measures from an NDT. In that NDT I also defined a measure for calculating standard deviation of avg daily usage:

Screenshot 2: NDT View

To test that I constructed this NDT correctly, I checked the std_dev measure across every row expecting to get an error or 0, but I get what looks like very tiny numbers. Okay fine, even if I ignore that and remove all the dimensions to get the population standard deviation I get an incorrect answer. FWIW I tried the min, max, average measure types in the NDT above and they seem to all work.

I’m I doing any of the above incorrectly?

Thanks!