...
Parting ponder-able: The final 'mapping' in #3 can be pretty arbitrarily defined... Berkeley's example uses spring injected lists to map 'A-' to 'P' for instance. But, we can calculate the proportion of dark matter in the Universe to determine our mapping, we don't have to use a static scale.
Questions:
1. Shat What are the scales assoc.'d with each of the above codes?
2. what are the standard mappings from standard grading scales to the scales in #1?