Question

The mean of 8 observation was found to be 20. Later it was detected that one of the observation was misread as 62. What is the correct observation if the correct mean is 15.5?

• A. 26
• B. 28
• C. 30
• D. 29

Answer 1

The correct option is A 26

Given, average of $8$ observation $=20$
$\frac{Sumof8observations}{8}=20$
$=>$ Sum of $8$ observations $=20\times 8=160$
Let the correct observation be $x$
Then, Sum of $8$ observations $=160-62+x=98+x$
Given correct mean $=15.5$
$\frac{98+x}{8}=15.5$
$=>98+x=124$
$=>x=26$
So, correct observation $=26$