Standard Deviation - Rates

[boehnc]

Still trying to figure out how to calculate a Standard Deviation and plot on a pivotchart when the data is rates.

Table1.Month, Table1.Incidence, Table1.Population, Table1.Rate
Jan-16, 4, 2000, .002
Feb-16, 2, 1934, .001
March-16, 6, 2012, .002
April-16, 8, 2114, .003


Id like to calculate the ave and standard deviation of the rate, but Powerpivot DAX only allows the SD to be calculated on a column, not a calculated measure. I plan to convert the rate to incidences per 1000 and plot and be able to have the SD change depending on the Year slicer selected. Thanks for any suggestions.

 

[Ozeroth]

Hi boehnc,

The STDEVX.S and STDEVX.P functions return the standard deviation of an expression evaluated over a table, and may do what you want.

For example, you could write a measure like:

=
STDEVX.S ( Table1, DIVIDE ( Table1[Incidence], Table1[Population] ) * 1000 )

The first argument can be any table for which each row represents the granularity of a data point
The second argument can be any scalar expression (measure or other expression that can be evaluated in the row context of the first argument).