Mean of 50 observations was found to be 80.4. But later on it was discovered that 96 was misread as 69 at one place. Find the correct mean. If to each observation a constant value k is added, how is the mean affected?
mean of 50 observations = 80.4
the sum of 50 observations = 80.4*50=4020
since 96 was misread as 69 at one place .
the actual sum = 4020-69+96=4047
therefore the correct mean = 4047/50= 80.94
if k is added to each observation.
the sum of n observations = 4047+50k
therefore the mean = (4047+50k)/50 = 80.94+k
hope this helps you.