I am trying to incorperate a cumulative frequency up to the data sets median within a chart dimension (The data set is below). The ideal outcome is that the function will return the total number people that waited less than the median for each month. The function I am using is
What you are experiencing is an inherent restriction with set analysis. Set analysis is calculated once per chart, and does not understand what dimension it's currently in. You might want to use "total" with a "<>" (subtotal) qualifier, in combination with some conditional function(s), to achieve your results.