25th and 75th Percentile incorrect for even observations

[S_N_L_A]

I have a DAX-measure where I want to receive the 25th and 75th percentiles of the data in a column. I have added a slicer and want the percentiles to update accordingly. Note that I have a Measure for median as well that works fine. Whenever I have an uneven amount of observations, the outcome seems to be correct. But whenever I have an even number of observations it seems to be incorrect. I've tried both Percentilex.inc, Percentilex.exc, Percentile.inc, and percentile.exc but cannot get my head around it.

Anyone that has encounterd the same issue?

Formulas used are the following

***3rd quartileAGETEST = CALCULATE (PERCENTILE.INC('Population data'[Age],0.75))

***1st quartileAGETEST = CALCULATE (PERCENTILE.INC('Population data'[Age],0.25))

Below are print screens of the visual and a table to show the data with the values used.

Expected outcome (uneven number of observations)

unexcpected(should be (57+54)/2=55,5 and (53+51)/2=52)

[S_N_L_A]

Hi!

Problem is still very present unfortunately.  Haven't been able to try it in a different version, but version info below:

[S_N_L_A]

Ps.

Got the info that the calculation formula and interpolation done when using percentile differs from my "idea" of what it should be. meaning my interpolation in this scenario is 51 + 0.25 * (53 - 51) = 51.5.

Say that I would not want this method, but instead identify the quartiles as I explained above (meaning identifying the middle value of each half). Do you know how I'd be able to do so?

[Anonymous]

Hi @S_N_L_A ,

Can you share the version of Power BI Desktop you are using and if the issue still exists in a different version?

Best Regards,
Adamk Kong