2016 · Q90
The mean of 20 observations is 17. On checking it was found that the two observations were wrongly copied as 3 and 6. If wrong observations are replaced by correct values 8 and 9, then what is the correct mean ?
Elementary MathematicsStatistics
- A17.4
- B16.6
- C15.8
- D14.2
Explanation
The corrected total is 20×17 −3−6+8+9 = 348. Dividing by the 20 observations gives the corrected mean 348/20 = 17.4. Hence option A.