Question

The mean of 100 observations is 50. If in one of the observations 50 is replaced by 150, the resulting mean will be

• A. 50.5
• B. 51
• C. 51.5
• D. 52

Answer 1

Answer: (B)

51

Mean of 100 observations = 50

$\Rightarrow \frac{\text{Total}}{100}=50\Rightarrow \text{Total}=5000$

50 is replaced by 150, hence the difference between the values $=150-50=100$

$\therefore \text{new total}=5000+100=5100$

New mean $=\frac{5100}{100}=51$