Hi there - my apologies in advance if my question / situation has been addressed in a previous posting.
I'm a newbie to Tableau Desktop, and am creating a number of worksheets. On one of them, I'm trying to show a running total of a subsegment and the total population for each month along with the subsegment's percentage of the total population - screenshot below.
The % Population Segment field has been calculated by taking a Sum of the records matching the population segment criteria (a Booelan), and dividing it by a Count of the Number of Records. This calculation works beautifully for each individual month; now I'm tryingi to figure how how to show this percentage on a weighted YTD basis for each month. I created a Moving Average table calculation on this field, moving across the table and against the previous 12 values. Things look good from Jan to April; then the moving average % starts to differ from the actual Population Segment/Population Total quotient. For example - in June dividing 1696 by 1816 results in 93.39% - yet my Moving Average calculation comes to 93.19%.
Any suggestions on what I should do to show the correct % Population Segment?