The mean of 100 observation is 50. If one of the observation which was 50 is replaced by 150, the resulting mean will be

Options

A. 50.5
B. 51
C. 51.5
D. 52

Answer

B

Explanation

We have `bar(x)=(sumx_(i))/(n)`
`rArr 50=(sumx_(i))/(100) rArr sumx_(i) = 50 xx 100=5,000`
If one of the observations which was 50 is replaced by 150, then
`sumx_(i)=5,000-50+150=5100`
Then, the resulting mean `=(5100)/(100)=51.`
Hence, (b) is the correct answer.