Simplify the following text for a Grade 13 native English-speaking person.
Original: Eunice Kathleen Waymon ( February 21 , 1933 â `` April 21 , 2003 ) , better known by her stage name Nina Simone , was an American singer , songwriter , pianist , arranger , and civil rights activist widely associated with jazz music .
Simplified: Nina Simone ( born Eunice Kathleen Waymon ; February 21 , 1933 â `` April 21 , 2003 ) was an American singer , songwriter , pianist , arranger and civil rights activist .