Median in Pivot table

Hi

In attached I have a two column table. Trying to find Medians / Percentiles via a new measure in the pivot table but getting an error. (Blank values must remain in the table for other reasons)

Not sure why / how to fix..

Q

The error message for the measure states that MEDIAN does not support types string/Boolean/date.
Looking at the data model the study scores are of the type text (string) which can not be changed in the data model.
My suggestion of how to fix is to produce a second table (green/white) using power query, add the new table to the data model, add the MEDIAN measure and then produce the pivot table.
The power query code is:

let
    Source = Excel.CurrentWorkbook(){[Name="Table2"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Study Score ", Int64.Type}, {"Subject Code", type text}}),
    #"Filtered Rows" = Table.SelectRows(#"Changed Type", each ([#"Study Score "] <> null))
in
    #"Filtered Rows"

Note that when data is updated in the original blue/white table then refresh the green/white table (and the pivot table if necessary).
Let us know if you have any questions.