Question

The mean of 24 observations is 72 . It was detected that one observations 53 was wrongly copied as 72 . Find the correct mean

Answer 1

X1+X2+X3+........+x24÷24=72
X1+.......X24-19=72*24
X1+......x24=1747
new average=X1+X2+......x24÷24=72.7916667