Eduprobe
Question:
A teacher wanted to analyze the performance of two sections of students in a mathematics test of 100 marks. Looking at their performance, she found that a few students got under 20 marks and a few got 70 marks or above. So she decided to group them into intervals of varying sizes as follows: 0-20, 20-30, ..., 60-70, 70-above. Then she formed the following table. (i) Find the probability that a student obtained less than 20?
Solution:
Total students = 90
(i) Number of students getting less than 20 = 7
Probability that a student obtained less than 20 = (Number of students getting less than 20) / (Total number of students)
= 7/90