The View Toolbar in a map view includes three different selection tools: radial, rectangular and lasso. When I use any of these tools to select data points, a view pops up with a summary of the selected data points (this summary is attached), but this summary just gives a sum of one of the classes of data I am mapping -- in this case, the sum of CO2 emissions from selected power plants. The text is also non-intuitive to someone not familiar with Tableau or with how I named data columns in the underlying data set -- it is given as the SUM of AVG(data).

1. How do I choose which data are shown in the summary when the selection tool is used (e.g. a sum of NOx emissions rather than CO2 emissions) or show the sum of multiple pieces of data (e.g. the sum of NOx emissions and the sum of CO2 emissions)?

2. How do I edit the text so that instead of SUM of AVG(data) I can write something like "Sum of average annual CO2 emissions (tons)"?

Thanks!