InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
The mean of 25 observations is 36. If the mean of the first 13 observations is 32 and that of the last 13 observations is 39, find the 13th observation. |
|
Answer» Let the 13th observation be x Given that mean of 25 observations = 36 ∴ sum of 25 observations = 25 × 36 = 900 Mean of the first 13 observations = 32 Sum of first 13 observations = 13 × 32 = 416 Mean of the last 13 observations = 39 Sum of the last 13 observations = 13 × 39 = 507 Therefore, Sum of first 13 observations + sum of last 13 observations – 13th observation = sum of 25 observations 416 + 507 - x = 900 ⇒ 923 – x = 900 ⇒ x = 23 |
|