Question

The marks (out of $100$) obtained by a group of students in science test are $85,76,90,84,39,48,56,95,81$ and $75$. Find the
(i) highest and the lowest marks obtained by the students.
(ii) range of marks obtained.
(iii) mean marks obtained by the group.

Answer 1

In order to find the highest and lowest marks, let us arrange the marks in ascending order as follows:
$39,48,56,75,76,81,84,85,90,95$
(i) Clearly, the highest mark is $95$ and the lowest is $39$.
(ii) The range of the marks obtained is:
highest mark $-$ Lowest marks $=(95-39)=56$
(iii) We have:
Mean marks $=$ Sum of the marks $÷$ Total number of students
$\Rightarrow$ Mean marks $=\frac{(39+48+56+75+76+81+84+85+90+95)}{10}=\frac{729}{10}=72.9$
Hence, the mean marks of the students is $72.9$