(2) The pass rate is 48? 348× 100%=93.8%
(3) The average score is: 55× 3+65×12+75×15+85× 9+95× 348 = 65 (minutes).
(4) The median falls within 70-80 groups; Only three people failed this course.
So the answers are: (1)48, (2)93.8, (3)65, (4) the median falls within the subgroup of 70-80; Only three people failed this course.
The four formulas of 5 and 5 are 5+5= 10 and 5-5=0. A figure four formula refers to writing two addition formulas and two subtraction formulas according to 5