I am using ArcMap 10.6.
I have a table with country data. I am interested in Asia only, so I created a new layer (and shapefile). Several countries have missing data, which was filled with the same value (-50). One of the fields is Life Expectancy and another is Access to Drinking Water(population percent). I classified the Life Expectancy field (about 30 unique values) into 5 classes (in the symbology tab). I don't know how to group the countries by class (in the attribute table) so I can calculate various stats by class.
For example, What is the mean Access to Drinking Water, by Life Expectancy class?