Question

mean of 50 observation 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

Answer 1

total no. of obs.=50
mean(x)=80.4
             =sigmaXi/n
=> 80.4=sigmaXi/50
=>sigmaXi= 80.4*50=4020
correct sigmaXi= 4020(96-69)=4020+27=4047
correct mean= correct sigmaXi/50
                     =4047/50=80.94