MARKS : 100-150 (students 60), 150-200( students 100), 200-300(students 100), 300-500( students 80), 500-800( students-180), if the student selected at - Maths - Statistics

Question

MARKS : 100-150 (students 60), 150-200( students 100),
200-300(students 100), 300-500( students 80), 500-800(
students-180), if the student selected at random from a class, find
the probability, that student is: (i) having marks less than 200
(ii) having marks between 150-300 (iii) having marks more than 150

Lalit Mehra · Accepted Answer

The marks scored by the students are given below in the form of a
frequency distribution table:

Marks
100-150
150-200
200-300
300-500
500-800

Number of Students
60
100
100
80
180

Total number of students = 60 + 100 + 100 + 80 + 180 = 520
1
Number of students having marks less than 200 = 60 + 100 = 160
Probability that the student has marks less than 200
= Number of students having marks less than 200/Total number of
students
= 160/520
= 4/13
2
Number of students having marks between 150-300 = 100 + 100 =
200
Probability that the student has marks between 150-300
= Number of students having marks between 150-300/Total number of
students
= 200/520
= 5/13
3
Number of students having marks more than 150 = 100 + 100 + 80 +
180 = 460
Probability that the student has marks more than 150
= Probability that the student has marks more than 150/Total number
of students
= 460/520
= 23/26

Marks	100-150	150-200	200-300	300-500	500-800
Number of Students	60	100	100	80	180