Question

The marks scored out of 1000 by some students in an examination are given below in the form of a frequency distribution table.(3) point is Marks 75% or more but less than 95%.

Answer 1

let the probability of getting marks 75% or more but less than 95% be E1

Favourable outcomes to E1 are 440

Total number of outcomes to E1 are 660

favourable outcomes P(E1)=________________
Total number of outcomes

440
= _____
660

22
= __
33

Answer 2

Total number of students = 660.

1) we have not the information on number of students getting less than 50% marks. Assuming that no one got below 500 marks,
Ans: prob (marks < 750)
= (25+30+150)/660 = 41/132

2) prob(marks < 50%) = 0

3) prob( 750 <= marks < 950) = (240+ 150 + 50) / 660
= 440/660 = 2/3