(2) As shown in the figure (Attachment (1), group median 1)

(3) 70 ~ 80 (or fill in 70.5-80.5 to give extra points)

(4) 14+540× 100%=47.5%

A: Omit.

(5)55.5×2+65.5×9+75.5× 10+85.5× 14+95.5×540

=78.25 (points)

The average score of this math exam is 78.25.