The mean of 20 observations was 85, but later it was found that 97 was misread as 79. The correct mean is:
Answer & explanation
Correct answer: option 4
Here,
\(\frac{Sum}{20}\) = 85,
⇒ Sum = 1700.
According to the question,
97 was misread as 79
Therefore, 97 - 79 = 18 will be added to the sum
⇒ New Sum = 1700 + 18 = 1718
⇒ \(\frac{1718}{20}\) = 85.9