The marks obtained by 10 students in a test are $60,72,70,64,56,52,71,54,62,59$. Find the mean marks of the students. Find the mean marks of the students if 6 extra marks are given to each student.

Given :

The marks obtained by 10 students in a test are $60,72,70,64,56,52,71,54,62,59$.

To do :

We have to find the mean marks of the students.

Solution :

Number of observations $= 10$.

We know that,

$Mean = \frac{Sum\ of\ the\ observations\ of\ the\ given\ data}{Number\ of\ observations}$

Therefore,

Mean marks $= \frac{(60+72+70+64+56+52+71+54+62+59)}{10}$

$= \frac{620}{10}$

$= 62$

6 extra marks are given to each student.

New mean marks $= \frac{(60+6)+(72+6)+(70+6)+(64+6)+(56+6)+(52+6)+(71+6)+(54+6)+(62+6)+(59+6))}{10}$

$=\frac{620+60}{10}$

$=\frac{680}{10}$

$=68$

The initial mean marks of the students is 62 and the new mean marks of the students is 68.