Original sentence: Piano Majors are known for having long times to rehearse on their own.The Choir department is split into two groups per session: the SATB choir,the lowest level chior, the SSA choir, a higher level group w/ better sight reading skills, and the Chamber Choir made up of  advanced campers from the other two chiors
Edited sentence: Piano Majors are known for having long periods to rehearse on their own.The Choir department is split into two groups per session: the SATB choir, the lowest level chior, the SSA choir, a higher level group, and the Chamber Choir, which is made up of  advanced campers from the other two chiors