Question

The mean of 100 observations is 50. If the observation 50 is replace d by 150,what will be the resulting mean?

Answer 1

Given mean of 100 observations = 50

Hence sum of observations = mean × number of observations
                                                = 50 × 100 = 5000

Given that one observation 50 is replaced with 150, which means and additional 100 is added to the sum of the observations.

So we need to add this 100 to the sum of the observations to get the correct sum of observations.

Hence correct sum of observations = 5000 + 100 = 5100 

Therefore the correct mean or resulting mean = 5100 / 100 = 51

Hope This Helps :)