Question

the mean of 5 observations is 50.one of the observation was removed from the data hence the mean became 45.find the observation which was removed ?

Answer 1

Mean of 5 observations = 50
Sum of 5 observations = 50*5= 250
Mean of 4 observations = 45
Sum of 4 observations = 45*4 = 180
Therefore, the excluded observation = 250-180 = 70

Answer 2

The mean of 5 observation is 50

•°•Sum of 5 observation =5×50=250

The mean of remaining 4 observation is 45(because 1 is removed)

•°•Sum of 4 observation =4×45=180

•°•Observation that was removed=sum of 5 observation - sum of 4 observation

=250 - 180 = 70