Question

The mean of eight observations is $25$.If onc observation $11$ is excluded, find the mean of the remaining observations.

• A. $37$
• B. $27$
• C. $77$
• D. $57$

Answer 1

The correct option is B $27$

Mean of $8$ observation $=\frac{\text{Sum of 8 observations}}{\text{Total number of observations}}$

$\Rightarrow 25=\frac{\text{Sum of 8 observations}}{8}$

$\Rightarrow \text{Sum of 8 observation}=200$

It is given one observation $11$ is excluded.

Then, number of observations left $=8-1=7$

And, Sum of $7$ observations $=200-11=189$

Then, New Mean $=\frac{\text{Sum of 7 observations}}{7}=\frac{189}{7}=27$

So, $\text{B}$ is the correct option.