Question

The mean of 150 items was found to be 60. Later on, it was discovered that the values of two items were misread as 52 and 8 instead of 152 and 88 respectively. Find the correct men.

Answer 1

Mean of 150 items = 60
Sum of 150 items = $(150\times 60)=9000$
New sum = [9000 $-$ (52 + 8) + (152 + 88)] = 9180

Correct mean = $\frac{\mathrm{New}\mathrm{sum}}{\mathrm{Total}\mathrm{items}}=\frac{9180}{150}=61.2$

Therefore, the correct mean is 61.2.