Question

Mean of 100 observations is 45. It was later found that two observations 19 and 31 were recorded incorrectly as 91 and 13, then the correct mean is
1. 44.46
2. 44
3. 45
4. None of these

Answer 1

Correct Answer - Option 1 : 44.46

Given:

Total number of observations = 100

Mean = 45

Formula used:

Mean = Sum of all the terms/Total number of terms

Calculation:

Sum of the incorrect observations = 45 × 100 = 4500

Sum o the correct observations = 4500 - (91 + 13) + (19 + 31)

⇒ 4446

Correct mean = 4446/100 = 44.46