NTA Abhyas JEE Main2020MathematicsStatisticsPractice
In an experiment with 9 observations on x , the following results are available ∑ x 2 = 360 and ∑ x = 34 . One observation that was 8 , was found to be wrong and was replaced by the correct value 10 , then the corrected variance is
Options
- A250 9
- B28
- C240 9
- D28
Correct answer
B. 28
Step-by-step solution
∑ x 2 = 360 , ∑ x = 34 corrected ∑ x ' = 34 – 8 + 10 = 36 corrected ∑ x ' 2 = 360 + 100 – 64 = 396 The corrected variance = ∑ x ' 2 9 – ∑ x 9 2 = 396 9 – 36 9 2 = 44 – 16 = 28