`barX=(sumX)/N`
Or, `sumX=barXN`
Given: `barX=40,N=100`
`40=(sumX)/100`
`:.sumX"(wrong)"=40xx100=4,000`
Correct value = 53
Incorrect value=83
Correct
`barX=(sumX"(Wrong)+(Correct value)-(Incorrect value)")/N`
`=(4,000+53-83)/100`
`=(3,970)/100=39.70`
Thus, Corrected Mean = 39.70.