The grand total in the second image is providing an average for the grand total column. Since the counts in that image are averages, the grand total will also be an average and not sum.
Miguel, that's the danger of using the automatic grand total calculations.
169 is the average of the monthly grand totals. It is NOT the total of the Grand Total column.
Just like the Grand Total values for each of the monthly columns are the averages of the values in the column, NOT the SUMs of those values.
Thanks to replying me back. Do you have any suggestion?
I created my own Grand Total in other data visualization tools, but in Tableau, I feel that I am a newbie with the Grand Totals. I do not have any idea how to create my own Grand Totals.
Don't feel too bad about it: it confuses all of us sometimes!
I guess the question is, what result do you want? Should the columns in your second image (for the Averages) be the TOTAL of the AVERAGE values above (so, December 2017 = 362+2+8=372)? Or should it be 124 (the average of 362, 2 and 8)?
What should that Grand Total column be? In your screen shot, the Grand Total values are the average of the 12 values to the right. Is that what you want? Or should they be the SUM of those values? Or something else?
Start there, then we'll see what we can do.
I need the average for each row line. For example, the three numbers for November (396+1+9) should be equal to 406. All the Grand Total numbers for each month in the columns is the sum of the three numbers. Please check the following images: The first image is from Xtraction output that I need in Tableau. The second image is from Tableau.