The short answer: 20 (composite score) is the national ACT average. About half of students score above that, and half of students score below. The top 25% of ACT takers score about 24 or more, so if your score is above 24, that's excellent.
1 SavinâNorov machine gun. 2  Space Network, a NASA relay satellite system. 3  Sthene, an obsolete unit of force or thrust in the metre-tonne-second system of units. 4  Substantia nigra, a brain structure. 5  Supernova, a stellar explosion, in astronomy and cosmology.  Tin, a metallic element with chemical symbol Sn.
Accepted 17 January 2013, Available online 15 March 2013. Schmorl's nodes (SN) are common lesions that represent disc material prolapse through the vertebral endplate, into the vertebral body with generally limited clinical significance. Rarely they have been related to the onset of back pain, usually self-limited.