The mean of 100 observations was calculated as 40. It was found later on that one of the observations was misread as 83 instead of 53. The correct mean is:
Mean of 100 observations = 40
=> Sum of 100 observations = $$100 \times 40=4000$$
Now, replacing 53 instead of 83
=> Correct sum = $$4000-83+53=3970$$
$$\therefore$$ Correct mean = $$\frac{3970}{100}=39.7$$
=> Ans - (B)
Create a FREE account and get:
