I haven't actually done the test, but I'd assume then that you need to look into the subclasses, like Of or A1V in order to get into the allowable range.
Yes, I think that's what you might have to do, but it seems to me that pinpointing the exact subclass based on a diagram would be very difficult to do precisely. I wonder what the test writer was intending.
On a separate note, what Astronomy textbooks have people found to be good for this event? I've been using Astronomy: A Self-Teaching Guide
, which is clear and concise, but it's definitely not in-depth enough for the material on the Nationals tests.
I've been using Carrol / Ostlie's Introduction to Modern Astrophysics
It's a VERY strong text, and has a good balance have math and concepts.
2013: Astro (2, 6) / Chem (2, 5) / Circuits (8, 36) / Diseases (1,1) / Fermi (N/A, 24) / Materials (1, N/A)
2012 : Astro (1, 11) / Chem (N/A, 13) / Diseases (3, 1) / Optics (2, 3) / Sounds (2, 1)
2011: Astro(2,11) / Diseases (1,27) / Optics (1,13) / Proteins (2,15)